WO2005106564A1 - Laser processing apparatus - Google Patents

Laser processing apparatus Download PDF

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Publication number
WO2005106564A1
WO2005106564A1 PCT/JP2005/008003 JP2005008003W WO2005106564A1 WO 2005106564 A1 WO2005106564 A1 WO 2005106564A1 JP 2005008003 W JP2005008003 W JP 2005008003W WO 2005106564 A1 WO2005106564 A1 WO 2005106564A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser
optical system
light
lens group
medium
Prior art date
Application number
PCT/JP2005/008003
Other languages
French (fr)
Japanese (ja)
Inventor
Yukio Eda
Sadashi Adachi
Norio Kurita
Tetsuya Osajima
Original Assignee
Olympus Corporation
Hamamatsu Photonics K.K.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2004132997A external-priority patent/JP4686135B2/en
Priority claimed from JP2004132995A external-priority patent/JP4681821B2/en
Application filed by Olympus Corporation, Hamamatsu Photonics K.K. filed Critical Olympus Corporation
Priority to EP05737135.3A priority Critical patent/EP1684109B1/en
Publication of WO2005106564A1 publication Critical patent/WO2005106564A1/en
Priority to US11/450,801 priority patent/US7333255B2/en
Priority to US11/868,210 priority patent/US8022332B2/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/03—Observing, e.g. monitoring, the workpiece
    • B23K26/032—Observing, e.g. monitoring, the workpiece using optical means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/04—Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
    • B23K26/046—Automatically focusing the laser beam
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
    • B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
    • B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
    • B23K26/0665—Shaping the laser beam, e.g. by masks or multi-focusing by beam condensation on the workpiece, e.g. for focusing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/36—Removing material
    • B23K26/40—Removing material taking account of the properties of the material involved
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K26/00—Working by laser beam, e.g. welding, cutting or boring
    • B23K26/50—Working by transmitting the laser beam through or within the workpiece
    • B23K26/53—Working by transmitting the laser beam through or within the workpiece for modifying or reforming the material inside the workpiece, e.g. for producing break initiation cracks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2101/00—Articles made by soldering, welding or cutting
    • B23K2101/36—Electric or electronic devices
    • B23K2101/40—Semiconductor devices
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K2103/00—Materials to be soldered, welded or cut
    • B23K2103/50—Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26

Definitions

  • the present invention relates to a laser focusing optical system that focuses laser light on different portions in a medium and a laser processing device.
  • the present invention relates to a laser processing apparatus capable of changing a light source position while keeping a light amount incident on a pupil plane of an optical system and a light amount distribution constant.
  • the present invention relates to an optimum laser processing apparatus capable of condensing laser light on a portion having a different depth in a medium, or a laser processing apparatus suitable for changing a condensing position.
  • a processing apparatus that cuts an object to be cut such as a semiconductor wafer or glass by using a laser beam is known.
  • This processing apparatus performs a cutting process by generating a modified layer or the like in a medium by condensing a laser beam having a laser beam source power by a condensing optical system.
  • the thickness of the object to be processed varies, so it is not always necessary to focus the light at the same depth. Is needed. That is, there is a demand that the light is focused at different depths in the medium.
  • a microscope correction ring with a magnification of about 40 times and a numerical aperture NA (Numerical Aperture) of 0.93 is excellently corrected over an ultra-wide field of view, and there is little deterioration in performance due to variations in cover glass thickness.
  • NA numerical aperture
  • a spherical aberration correction lens 232 is disposed between the objective lens 230 and the light source 231 and the spherical aberration is corrected by moving the spherical aberration correction lens 232 along the optical axis.
  • a microscope device that performs the following (for example, see Patent Document 3).
  • Patent Document 1 JP-A-5-119263 (Fig. 1 etc.)
  • Patent Document 2 Japanese Patent Application Laid-Open No. 2003-175497 (FIG. 1 etc.)
  • Patent Document 3 Japanese Patent Application Laid-Open No. 2001-83428 (FIG. 1 etc.)
  • the spherical aberration can be corrected by moving the spherical aberration correction lens 232 in the optical axis direction. With the movement of the aberration correction lens 232, the diameter of the light beam incident on the objective lens 230 changes.
  • the spread of the light beam changes. Therefore, as shown in FIG. 21, the amount of light changes, and the brightness on the sample surface changes.
  • the brightness of the image is detected, and the power of the light source is changed according to the brightness.
  • the brightness can be made constant by controlling the brightness on the image side, but there is a problem that the device configuration becomes complicated.
  • the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser focusing optical system and a laser processing apparatus that can easily perform spherical aberration correction with a simple configuration without trouble. I do.
  • the present invention employs the following solutions.
  • a laser condensing optical system of the present invention comprises: a laser light source for emitting laser light; a condensing optical system disposed between the laser light source and a medium for condensing the laser light in the medium; The position of the laser divergence point of the laser light was determined according to the refractive index of the medium to which the laser light was to be focused and the laser light from the surface of the medium! / According to the distance to the position. Means for moving the laser divergence point along the optical axis of the light.
  • the laser light emitted from the laser light source by the condensing optical system can be condensed in a medium.
  • the laser light is incident on the focusing optical system in a divergent light state (non-parallel light beam state). That is, the light is emitted from the laser light source in a divergent light state, or emitted in a parallel light flux state by the laser light source, converted into a divergent light state by various lenses, and is incident on the condensing optical system.
  • the point at which the laser light enters the diverging light state is referred to as the diverging point.
  • the laser divergence point moving means sets the laser divergence point by the laser divergence point moving means according to the refractive index of the medium to be condensed and the distance to the position condensed from the surface of the medium. Since the laser beam is moved along the optical axis, even if the laser light is focused on the medium at different depths, the amount of spherical aberration generated at each position can be minimized. Therefore, the laser light can be efficiently condensed to a desired depth of the medium, and the light condensing performance can be improved.
  • the laser divergence point is merely moved, spherical aberration correction can be easily performed without any trouble as in the related art.
  • the configuration can be simplified and the cost can be reduced.
  • it is only necessary to move the laser divergence point it is easy to cope with automation that can easily be continuously varied.
  • the laser divergence point moving means may set the position of the laser divergence point based on the wavefront data of the condensing optical system measured in advance.
  • the laser divergence point moving means may measure the wavefront data of the condensing optical system measured in advance, for example, the wavefront data of the objective lens which is a part of the condensing optical system, or the condensed light. Since the position of the laser divergence point is set in consideration of the wavefront data of the entire system, the laser light focusing performance can be further improved.
  • An observation optical system is provided in cooperation with the condensing optical system and maintains a predetermined distance from the lower surface of the condensing optical system to the surface of the medium.
  • a force detection means or an auto-focus mechanism may be provided!
  • the distance from the lower surface of the light collecting optical system to the surface of the medium can be maintained at a predetermined distance by the observation optical system.
  • the relative movement of the light collecting optical system and the medium in the horizontal direction can be maintained.
  • the relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium is constant.
  • a laser processing apparatus provided with the above laser focusing optical system may be employed.
  • a first aspect of the laser processing apparatus of the present invention is a laser light source for emitting laser light; parallel light beam means for converting the light beam of the laser light emitted from the laser light source to a parallel light beam; A condensing optical system for condensing the laser light in a state in a medium; movable in the parallel light beam between the parallel light beam means and the light condensing optical system along the optical axis direction of the parallel light beam A first lens group composed of one or more lenses; and a first lens group fixedly arranged in the parallel light flux between the first lens group and the condensing optical system.
  • a second lens group composed of one or more lenses; and V, the laser beam is focused, the refractive index of the medium and the laser beam focused from the surface of the medium! /, Depending on the distance to the position.
  • Moving means for moving the first lens group; wherein the second lens group is Point position is arranged at least near the entrance pupil position of the condensing optical system.
  • the emitted laser light is converted into a parallel light beam by the parallel light beam means and refracted by the first lens group and the second lens group, respectively. And is collected in the medium.
  • the light source position can be moved in the optical axis direction. That is, by moving the first lens group, the position of the light source viewed from the second lens group can be changed, and further, the position of the light source can be substantially changed while also looking at the power of the condensing optical system. Condensed! /, Condensed from the medium's refractive index and the surface of the medium!
  • the position of the light source can be changed, and the laser beam can be focused at a desired position (depth) while minimizing the amount of spherical aberration generated. Therefore, the laser beam can be cut with high precision, and for example, a wafer or the like can be cut more accurately.
  • the rear focal position of the second lens group and the entrance pupil position of the condensing optical system are arranged so as to match, so that even if the first lens group moves along the optical axis, the first lens group is moved.
  • the parallel luminous flux incident on the group always has the same luminous flux diameter at the entrance pupil position of the converging optical system regardless of the position of the first lens group, and is condensed without being shaken by the converging optical system. That is, it is possible to reduce the change in the light amount at the light condensing position, and since the light amount distribution on the entrance pupil plane of the light collecting optical system does not change, the change in the light condensing performance can be suppressed.
  • the position of the light source can be changed only by moving the first lens group, there is no need to move the converging optical system, the stage, and the like in the optical axis direction as in the related art. Accordingly, the configuration can be simplified, and the spherical aberration can be easily corrected without any trouble. Further, unlike the conventional correction ring objective lens, it is not necessary to provide a special optical system, so that the configuration can be simplified and the cost can be reduced.
  • An observation optical system is provided in association with the condensing optical system and maintains a predetermined distance from the lower surface of the condensing optical system to the surface of the medium.
  • a force detection means or an auto-focus mechanism may be provided!
  • the distance from the lower surface of the light collecting optical system to the surface of the medium can be maintained at a predetermined distance by the observation optical system, for example, the horizontal relative movement between the light collecting optical system and the medium That is, when scanning, the depth from the medium surface can be accurately controlled to a desired depth.
  • the relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium may be constant.
  • the relative distance between the light-collecting optical system and the surface of the medium in the optical axis direction, that is, the WD is set to be constant, so that the autofocus mechanism can be configured more easily. This is possible and can be configured at low cost.
  • the moving means may move the first lens group to a position satisfying the following equation. Good.
  • the second lens group may satisfy the following expression.
  • the first lens group and the second lens group may satisfy the following equation! / ,.
  • the first lens group and the second lens group may satisfy the following equation! / ,.
  • a second aspect of the laser processing apparatus of the present invention includes a laser light source for emitting laser light; and a condensing optical system for condensing the laser light in a medium, and collects the laser light.
  • a plurality of lenses satisfying the following formula can be exclusively excluded during the convergence or divergence of the light collection optical system. It has a laser condensing optical system which is arranged in a function.
  • NA NA of light source (NA viewed from condensing lens)
  • a third aspect of the laser processing apparatus of the present invention includes a laser light source that emits a laser beam parallel to an optical axis; and an optical system that focuses the laser beam on a medium.
  • Laser beam was focused! / ⁇ Refractive index of the medium, focused from the surface of the medium! / ⁇ distance to the position Accordingly, there is provided a laser focusing optical system in which a plurality of lenses satisfying the following expression are exclusively and removably arranged in a laser beam.
  • the laser diverging point moving means is used in accordance with the condensed light !, the refractive index of the medium, and the distance from the surface of the medium to the position where the light is condensed. Since the laser divergence point is moved along the optical axis of the laser light, it is possible to minimize the amount of spherical aberration generated at different positions in the medium at different depths. Therefore, the laser light can be efficiently condensed to a desired depth of the medium, and the light condensing performance can be improved.
  • the laser beam can be efficiently focused at different depths in the medium while suppressing the occurrence of spherical aberration as much as possible.
  • Laser beam can be performed.
  • the first lens group depends on the refractive index of the medium to be focused and the distance from the surface of the medium to the position to be focused.
  • the position of the laser beam incident on the second lens group can be changed, that is, the light source position can be changed from the viewpoint of the condensing optical system, so that the spherical aberration can be changed to a desired position (depth).
  • the laser beam can be focused while minimizing the amount of light generation. Therefore, laser processing can be performed with high accuracy.
  • the second lens group whose rear focal position matches the entrance pupil position of the condenser optical system does not change the diameter of the light beam incident on the entrance pupil of the condenser optical system.
  • the light amount distribution in the plane can be made constant, and the change in the light collecting performance can be suppressed.
  • the position of the light source can be changed only by moving the first lens group, the configuration can be simplified, and spherical aberration can be easily corrected without any trouble.
  • FIG. 1 is a configuration diagram showing a first embodiment of a laser processing apparatus and a laser focusing optical system according to the present invention.
  • FIG. 2 is an example of a flowchart in a case where laser light is applied to positions of the wafer having different surface forces and depths by the same laser focusing optical system.
  • FIG. 3 is an example of a case where laser light is irradiated by the laser condensing optical system in consideration of wavefront data of the condensing optical system.
  • FIG. 4 is a configuration diagram showing a second embodiment of the laser focusing optical system according to the present invention.
  • FIG. 5 is an example of a flowchart in the case where laser light is applied to positions of the wafer having different surface forces and depths by the same laser focusing optical system.
  • FIG. 6 is a view showing a third embodiment of the laser condensing optical system according to the present invention, and is an example of a flowchart in a case where laser light is applied to positions on the wafer having different surface forces and depths.
  • FIG. 7 is a view showing a state where laser light is applied to positions of the wafer having different surface force depths according to the flowchart.
  • FIG. 8 is a configuration diagram showing a fourth embodiment of the laser focusing optical system according to the present invention.
  • FIG. 9 is an example of a flowchart in a case where laser light is applied to positions of the wafer having different surface forces and depths by the same laser focusing optical system.
  • FIG. 10 is a configuration diagram showing a fifth embodiment of the laser processing apparatus according to the present invention.
  • FIG. 11 is an example of a flowchart in a case where a laser beam is focused to a desired depth in a wafer by the laser processing apparatus.
  • FIG. 12 is a flowchart illustrating a laser processing apparatus according to a sixth embodiment of the present invention, and is an example of a flow chart in a case where laser light is focused to a desired depth in a wafer while keeping the WD constant. is there.
  • FIG. 13 is a configuration diagram showing a seventh embodiment of the laser processing apparatus according to the present invention.
  • FIG. 14 is a configuration diagram showing an eighth embodiment of the laser processing apparatus according to the present invention.
  • FIG. 15 is a configuration diagram showing a ninth embodiment of the laser processing apparatus according to the present invention.
  • Fig. 16 is a diagram showing a laser processing apparatus in which a plurality of convex lenses are arranged so as to be able to be removed from a divergent light beam.
  • FIG. 17 is a view showing a laser processing apparatus in which a plurality of convex lenses are arranged so as to be able to be removed from a convergent light beam.
  • FIG. 18 is a diagram showing a laser processing apparatus in which a plurality of concave lenses are arranged in a parallel light beam so as to be detachable.
  • FIG. 19 is a diagram showing a laser processing apparatus in which a parallel light beam is converted into convergent light by a convex lens, and a plurality of concave lenses are removably arranged in the convergent light.
  • FIG. 20 is a diagram illustrating a conventional correction of spherical aberration, and is a diagram illustrating an example of an optical system capable of moving a spherical aberration correction lens in an optical axis direction.
  • FIG. 21 is a diagram showing a state in which the amount of light at the entrance pupil position changes by the optical system shown in FIG. 20.
  • the laser processing apparatus of the present embodiment performs laser processing while scanning in the horizontal direction in a state where the laser light L is focused on the wafer (medium) A, and cuts the wafer A into an arbitrary size.
  • the apparatus includes a laser condensing optical system 1 as shown in FIG.
  • the laser processing apparatus of the present embodiment has a stage that can move the wafer A in the horizontal direction and the vertical direction! /
  • the laser condensing optical system 1 includes a laser light source (not shown) that emits the laser light L in a parallel light beam state, and the laser light L
  • the position of the laser divergence point 3 of the laser beam L and the condensing optical system 2 including the objective lens etc. for condensing the laser beam L were condensed from the surface of the wafer A with the refractive index.
  • a laser divergence point moving means 4 that can move along the optical axis of the laser beam L according to the distance to the position.
  • the laser divergence point 3 is a position where the laser beam L emitted from the laser light source in a parallel light flux state is changed to a divergent light state (non-parallel light flux state) by a predetermined optical system. Is shown. However, when the laser light source is set to be able to emit the laser light source in a non-parallel light beam state, the position where the laser light source force is also emitted is the laser divergence point 3.
  • the laser divergence point moving means 4 is connected to a control unit (not shown), and moves the laser divergence point 3 in response to a signal from the control unit.
  • the control unit includes an input unit capable of inputting predetermined information, and a calculation unit that calculates a movement amount of the laser divergence point 3 based on each input information (input data) input by the input unit.
  • a signal is sent to the laser divergence point moving means 4 in accordance with the calculation result, and the laser divergence point moving means 4 is moved.
  • the control unit simultaneously controls the laser light source so as to emit the laser light L after the movement of the laser divergence point 3 is completed.
  • the laser beam L is condensed in the wafer A at positions having different surface forces and the depth of the wafer A is scanned, and the wafer A is scanned.
  • the case where the cutting is performed will be described.
  • a case will be described in which laser beams are condensed at positions different in depth, for example, at positions 50 m, 75 m, and 100 ⁇ m from the surface.
  • the refractive index of the wafer A and the surface force of the wafer A are collected at the input of the controller.
  • Input the distance to the position to be made, that is, 50 ⁇ m and the numerical aperture NA (Numerical Aperture) of the condenser optical system 2 (Step Sl).
  • the calculation unit calculates the amount of movement of the laser divergence point 3 based on the input data, that is, the distance between the laser divergence point 3 and the converging optical system 2, and the distance between the converging optical system 2 and the surface of the wafer A That is, the WD value is calculated (step S2).
  • control unit controls the laser divergence point moving means 4 to move in the optical axis direction of the laser beam L based on the calculation result, and as shown in FIG. Is moved to a predetermined position, and WD is changed by a moving means (not shown) so that the distance WD between the condensing optical system 2 and the wafer A becomes a calculated value (step S3).
  • the control unit sends a signal to the laser light source to emit the laser light L (Step S4).
  • the emitted laser light L enters a divergent light state at the position of the laser divergence point 3 moved to a predetermined position by the laser divergence point moving means 4, and then is condensed by the converging optical system 2 to 50 m from the surface of the wafer A. Is collected at the position.
  • the position of the laser divergence point 3 is adjusted in accordance with the depth of 50 m, the amount of spherical aberration can be suppressed as much as possible, and the laser beam L is moved to the position of 50 m. Light can be collected efficiently.
  • the control unit controls the laser divergence point moving means 4 to move in the optical axis direction of the laser beam L based on the calculation result, and obtains the results shown in FIGS. 1 (b) and (c). I'll show you As described above, the position of the laser divergence point 3 is moved to a predetermined position to change the WD. Thereafter, the laser beam L is emitted, and the laser beam L is focused by the focusing optical system 2 at a position of 75 ⁇ m or 100 ⁇ m from the surface of the wafer A.
  • the position of the laser divergence point 3 is adjusted according to the depth of 75 m or 100 m, so that the amount of spherical aberration generated at each position can be minimized,
  • the laser beam L can be efficiently focused at a position of 75 ⁇ m or 100 ⁇ m.
  • the energy is concentrated at one point (focus point) and a crack is generated.
  • the desired position Cracks can occur.
  • the stage is scanned in the horizontal direction and laser processing is performed, thereby connecting adjacent cracks to each other to make the wafer A have an arbitrary size. For example, it can be cut into chips.
  • the laser beam L is applied to the wafer A at different depths (50 m, 75 m, and 100 ⁇ m).
  • the laser divergence point 3 is moved along the optical axis by the laser divergence point moving means 4 according to the distance to the position where the refractive index of the wafer A and the surface force of the wafer A are condensed. Accordingly, the amount of generation of spherical aberration can be suppressed as much as possible, and the laser beam L can be efficiently condensed in an optimal state at each depth.
  • by performing scanning at each depth more accurate laser power can be obtained, and high-precision cutting can be performed.
  • the laser divergence point 3 since the laser divergence point 3 is simply moved, spherical aberration correction can be easily performed without any trouble as in the related art. In addition, since a special optical system such as a conventional correction ring objective lens is not required, the configuration can be simplified and the cost can be reduced. Furthermore, since the laser divergence point 3 is merely moved, it is easy to continuously change the size and it is easy to respond to automation.
  • the refractive index of the wafer A, the distance from the surface of the wafer A, the distance to the position, and the NA of the focusing optical system 2 are input to the input unit.
  • the input data is not limited to the above, and for example, The position of the laser divergence point 3 may be calculated by inputting, in addition to the input data, the previously measured wavefront data of the condensing optical system 2.
  • the condensing optical system 2 Input the NA and the wavefront data of the focusing optics 2.
  • spherical aberration correction can be performed with higher accuracy, and the light-gathering performance of the laser light L can be further improved.
  • the wavefront data of the condensing optical system 2 may be, for example, the wavefront data of the objective lens which is a part of the condensing optical system 2, or the wavefront data of the entire condensing optical system 2 may be used. It does not matter.
  • the difference between the second embodiment and the first embodiment is that in the first embodiment, the stage is simply moved when scanning is performed, but in the second embodiment, the focusing optical system 2 and the wafer A are moved. The point is that scanning is performed with the distance to the surface kept constant.
  • the condensing optical system 2 of the present embodiment is provided in cooperation with the condensing optical system 2, and the lower surface force of the condensing optical system 2 is the distance to the surface of the wafer A.
  • An observation optical system 10 for maintaining the distance at a predetermined distance is provided.
  • the observation optical system 10 has an autofocus mechanism.
  • the observation optical system 10 includes a light source 11 for irradiating linearly polarized semiconductor laser light L ′, a light source 11, a first lens 12 for making the irradiated semiconductor laser light L parallel, and a first lens 12. 12, a second lens 14 for converging the semiconductor laser light L transmitted through the polarization beam splitter 13, and a semiconductor laser light L converged by the second lens 14 again.
  • a fourth lens 19 that allows the return light from the condensing optical system 2 that has passed through and reflected by the polarization beam splitter 13 to be incident on the cylindrical lens 18 and a photodiode 20 disposed on the rear side of the cylindrical lens 18 Equipped with
  • the dichroic mirror 17 is set so as to reflect the semiconductor laser light L ′ and transmit light of other wavelengths, for example, the laser light L emitted from the laser light source.
  • the polarization beam splitter 13 transmits, for example, a linearly polarized light of P component, which is a vibration component parallel to the incident surface, of the linearly polarized light, and a vibration component S perpendicular to the incident surface. It has the function of reflecting component light. Further, the control unit performs feedback control of the stage based on a detection signal such as a focusing error signal received by the photodiode 20, and moves the stage in the vertical direction (optical axis direction). That is, automatic focusing is performed. Thereby, the semiconductor laser light L ′ is adjusted so that the surface of the wafer A is always focused.
  • a detection signal such as a focusing error signal received by the photodiode 20
  • the light source 11 when scanning the wafer A, the light source 11 irradiates the semiconductor laser light L ′ that is also linearly polarized.
  • the irradiated semiconductor laser light L ′ is converted into parallel light by the first lens 12 and then enters the polarization beam splitter 13.
  • the light becomes linearly polarized light having a P component, which is a vibration component parallel to the incident surface, and is then converged by the second lens 14 to be in a divergent state.
  • the diverged light becomes parallel light again by the third lens 15 and enters the 1Z4 wavelength plate 16.
  • the parallel light has the width of the light beam corresponding to the condensing optical system 2.
  • the semiconductor laser light L ′ that has passed through the 1Z4 wavelength plate 16 and has become circularly polarized is reflected by the dichroic mirror 17 and is incident on the condenser optical system 2.
  • the light incident on the condensing optical system 2 illuminates the surface of the wafer A.
  • the light reflected on the surface of the wafer A is condensed by the condensing optical system 2, is reflected by the dichroic mirror 17 and is incident on the 1 Z4 wave plate 16, and is perpendicular to the incident surface.
  • S-polarized light which is the vibration component.
  • This light passes through the third lens 15 and the second lens 14, then enters the polarization beam splitter 13 and is reflected toward the fourth lens 19. After being converged by the fourth lens 19, the light passes through the cylindrical lens 18 and is imaged on the photodiode 20.
  • the detection signal such as the focused focusing error signal is transmitted to the control unit. (Step S5).
  • the control unit calculates based on the sent detection signal (step S6), and moves the stage vertically (optical axis direction) so that the focus of the semiconductor laser light L 'is on the surface of the wafer A. (Step S7). That is, control is performed such that the automatic focusing is performed and the surface of the wafer A is always imaged.
  • the scanning is performed after the calculation of the amount of offset of the autofocus (step S8) is performed in advance.
  • the WD value must be changed along with the movement of the laser divergence point. It is necessary to set the optimum state, that is, the optimum value.
  • the WD value With the change of the WD value, it is necessary to offset the auto focus by a predetermined amount. In other words, the WD value can be corrected by calculating the autofocus offset amount. Then, after performing the offset, scanning at a different depth can be performed as described above.
  • the difference between the third embodiment and the first embodiment is that in the first embodiment, the relative distance in the optical axis direction between the light-collecting optical system 2 and the surface of the optics A, that is, the WD is constant. On the other hand, in the third embodiment, the WD is fixed.
  • the settings are made so that the positions of the two are always maintained at the same position.
  • the laser divergence point moving means 4 moves only the laser divergence point 3 along the optical axis direction while keeping the WD constant, so that the spherical surface can be simplified with a simpler configuration. Aberration correction can be performed.
  • the difference between the fourth embodiment and the second embodiment is that, in the second embodiment, the relative distance in the optical axis direction between the condensing optical system 2 and the surface of each of the optics and A, that is, the WD is constant. On the other hand, in the fourth embodiment, the WD is fixed.
  • the condensing optical system 2 of the present embodiment can perform scanning while performing auto-focusing with the WD kept constant, as in the third embodiment. Therefore, as shown in FIG. 9, there is no need to calculate the offset amount again after initially setting the offset amount of the autofocus, so that the time required for the offset can be reduced and the throughput can be improved.
  • the laser light is focused in the wafer, but the laser light may be focused not only in the wafer but also in the medium.
  • the distance to be focused is set to a distance of 50 m, 75 m, or 100 ⁇ m from the surface force of the wafer. The force is not limited to these distances, and may be set arbitrarily.
  • the relative distance in the optical axis direction between the condensing optical system and the surface of the wafer was changed by moving the stage.
  • the present invention is not limited to this.
  • the condensing optical system may use a piezo element or the like. The relative distance may be changed by moving the object.
  • the laser divergence point moving means is automatically controlled by the control unit.However, based on the calculation result by the control unit, the laser divergence point moving means is operated by the means to move the position of the laser divergence point. It doesn't matter.
  • the observation optical system described in the third embodiment is an example, and the lower surface of the converging optical system is As long as the distance to the surface of the wafer can be maintained at a predetermined distance, each optical system such as a lens may be combined.
  • a laser processing apparatus 101 of the present embodiment includes a laser light source (not shown) that emits a laser beam L, and a lens (not shown) that converts the laser beam L emitted from the laser light source into a parallel light beam. And a converging optical system 103 having an objective lens 102 for converging the laser beam L in a parallel light beam state into a medium; and a parallel light beam between the parallel light beam means and the objective lens 102.
  • a first lens (first lens group) 104 movably arranged along the optical axis direction of the parallel light beam, and a state fixed in the parallel light beam between the first lens 104 and the objective lens 102
  • the distance between the second lens (second lens group) 105 arranged at the point and the position where the laser beam L is condensed and the refractive index of the wafer (medium) A and the surface force of the wafer A are also condensed Moving means 106 for moving the first lens 104 in accordance with And an observation optical system 107 provided in cooperation with the main body to maintain a predetermined distance from the lower surface of the objective lens 102 to the surface of the wafer A.
  • the wafer A is mounted on a stage (not shown) that can move in the X and Y directions.
  • the first lens 104 is a biconcave lens, and is fixed to a lens frame (not shown).
  • the moving means 106 is connected to the lens frame, and moves the first lens 104 via the lens frame.
  • the moving means 106 is connected to a control unit (not shown), and operates by receiving a signal from the control unit.
  • the control unit includes an input unit capable of inputting predetermined information, and a calculation unit that calculates a movement amount of the first lens 104 based on each input information (input data) input by the input unit.
  • the moving means 106 is moved by a predetermined amount according to the calculation result.
  • the control unit also controls the laser light source so as to emit a light beam after the movement of the first lens 104 is completed, in addition to the control unit of the moving unit 106.
  • the second lens 105 is a convex lens, and the flat side faces the first lens 104 side, that is, the convex side faces the objective lens 102 side, and the rear focal position of the second lens 105 is incident It is arranged at a position at least near the pupil position.
  • the observation optical system 107 includes a light source 110 that irradiates a linearly polarized semiconductor laser light L ′, a first lens 111 that converts the semiconductor laser light L ′ emitted from the light source 110 into parallel light, A polarizing beam splitter 112 disposed adjacent to the first lens 111, a second lens 113 for converging and diverging the semiconductor laser light L ′ transmitted through the polarizing beam splitter 112, and a semiconductor diverged by the second lens 113.
  • a third lens 114 that converts the laser light L into parallel light, a 1Z4 wavelength plate 115 that converts the polarization of the semiconductor laser light L ′ transmitted through the third lens 114 into circularly polarized light, and a light that passes through the 1Z4 wavelength plate 115
  • the dichroic mirror 116 which reflects the semiconductor laser light L 'so as to change the direction of the optical axis by 90 degrees and makes it incident on the objective lens 102, is reflected by the polarization beam splitter 112 out of the return light from the objective lens 102.
  • Semiconductor laser A fourth lens 118 for allowing the light L to enter the cylindrical lens 117 and a photodiode 119 disposed on the rear side of the cylindrical lens 117 are provided.
  • the dichroic mirror 116 is set to reflect the semiconductor laser light L ′ and transmit light of other wavelengths, for example, the laser light L emitted from a laser light source.
  • the polarization beam splitter 112 transmits, for example, linearly polarized light of a P component, which is a vibration component parallel to the incident surface, of the linearly polarized light, and S component, which is a vibration component perpendicular to the incident surface. It has the function of reflecting light.
  • the control unit performs feedback control of the stage based on a detection signal such as a focusing error signal received by the photodiode 119 to move the stage in the vertical direction (optical axis direction). That is, automatic focusing is performed. Thereby, the semiconductor laser light L is adjusted so that the surface of the wafer A is always focused.
  • the distance between the lens 102 and the surface of the wafer A, that is, the WD value and the previously measured wavefront data of the objective lens 102 are input (step S1A).
  • the calculation unit calculates the data based on the input data.
  • the amount of movement of the first lens 104 is calculated (step S2A).
  • the control unit controls the moving means 106 in the optical axis direction based on the calculation result to move the position of the first lens 104 to a predetermined position (step S3A). ).
  • the control unit sends a signal to the laser light source to emit the laser light L (Step S4A).
  • the emitted laser light L is converted into a parallel light beam by the parallel light beam means and enters the first lens 104.
  • the laser light L is refracted by the first lens 104 to be in a divergent light state, and is incident on the second lens 105. That is, the position of the divergence point of the laser light L in the optical axis direction is changed by moving the first lens 104.
  • the divergent laser light L is refracted again by the second lens 105, then enters the objective lens 102, and is condensed to a desired depth (50 m) of the surface force of the wafer A.
  • the position of the first lens 104 is moved in the optical axis direction according to the desired depth to adjust the position of the divergence point, so that the amount of spherical aberration generated is minimized.
  • the laser beam L can be efficiently focused on a desired position.
  • the control unit operates the moving unit 106 based on the calculation result by the calculation unit to move the first lens 104 to a new position along the optical axis direction.
  • the laser light L is refracted at a position different from the above-mentioned position, enters a divergent light state, and enters the second lens 105.
  • the laser beam L is incident on the first lens 104 in a parallel light flux state, even if the laser beam L moves along the optical axis of the first lens 104, the light beam entering the first lens 104 If the distance (s) from the optical axis is constant, the angle (q) of the light beam after passing through the first lens 104 does not change (is parallel). The light rays (parallel) whose angles do not change converge (must pass) at one point on the rear focal plane of the second lens 105.
  • the rear focal position of the second lens 105 and the entrance pupil position of the condensing optical system 103 are arranged so as to be coincident with each other, and the parallel light beam incident on the first lens 104 is Irrespective of the position, the light beam diameter always becomes the same at the entrance pupil position of the condensing optical system 103, and the light is condensed without being shaken by the condensing optical system 103. Since the diameter of the light beam incident on the condensing optical system 103 does not change, it is possible to suppress the change in the light amount at the light condensing position and the change in the light amount distribution in the pupil plane as in the related art.
  • the laser beam L when the laser light L is focused on the wafer A, the energy is concentrated at one point (focus point) and a crack is generated.
  • the laser beam L can be condensed at positions having different depths while suppressing spherical aberration as much as possible, a crack can be accurately generated at a desired position.
  • the stage is scanned in the horizontal direction to perform laser processing, thereby connecting adjacent cracks to each other to make the wafer A to an arbitrary size. For example, it can be cut into chips.
  • the scanning can be performed with the distance between the objective lens 102 and the surface of the wafer A kept constant.
  • the light source 110 when scanning, the light source 110 emits linearly polarized semiconductor laser light L ′.
  • the illuminated semiconductor laser light L ′ is converted into parallel light by the first lens 111 and then enters the polarization beam splitter 112. Then, after becoming a linearly polarized light of a P component which is a vibration component parallel to the incident surface, the light is converged by the second lens 113 and then diverged. Then, the diverged light becomes parallel light again by the third lens 114 and enters the 1Z4 wavelength plate 115.
  • the parallel light has a light beam width corresponding to the objective lens 102.
  • the semiconductor laser light L ′ that has passed through the quarter-wave plate 115 and has become circularly polarized is reflected by the dichroic mirror 116 and enters the objective lens 102.
  • the light that has entered the objective lens 102 illuminates the surface of the wafer A.
  • the light reflected on the surface of the wafer A is condensed by the objective lens 102, then enters the 1 Z4 wave plate 115 reflected by the dike opening mirror 116, and vibrates perpendicularly to the incident surface.
  • the polarization of the S component which is the component.
  • This light passes through the third lens 114 and the second lens 113, then enters the polarization beam splitter 112, and is reflected toward the fourth lens 118.
  • the light passes through the cylindrical lens 117 and forms an image on the photodiode 119.
  • the formed detection signal such as a focusing error signal is sent to the control unit (step S5A).
  • the control unit performs a calculation based on the sent detection signal (step S6A), and moves the stage in the vertical direction (optical axis direction) so that the focus of the semiconductor laser light L 'is on the surface of the wafer A. (Step S7A). Immediately That is, automatic focusing is performed, and control is performed so that the distance between the condensing optical system 103 and the surface of the wafer A is always constant.
  • scanning can be performed while always keeping the distance between the objective lens 102 and the surface of the wafer A at a constant distance. Therefore, even if the stage is slightly curved or the stage moves with some error, the laser beam L can be accurately focused to a desired depth. Therefore, scanning can be performed while controlling the focusing position more accurately from the surface of the wafer A, and laser processing can be performed with higher precision.
  • the scanning is performed after the calculation of the amount of offset of the autofocus (Step S8A) is performed in advance.
  • the WD value should be set to the optimum value.
  • the change of the WD value a necessary force S for offsetting the auto focus by a predetermined amount occurs.
  • the WD value can be corrected by calculating the autofocus offset amount. After performing this correction, scanning at different depths is performed.
  • the difference between the sixth embodiment and the fifth embodiment is that, in the fifth embodiment, the relative distance in the optical axis direction between the objective lens 102 and the surface of the Ueno or A, that is, the force with which the WD is not constant. On the other hand, in the sixth embodiment, the WD is fixed.
  • a laser processing apparatus according to a seventh embodiment of the present invention will be described with reference to FIG.
  • the same components as those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted.
  • the difference between the seventh embodiment and the fifth embodiment is that, in the fifth embodiment, the first lens 104 is a biconcave lens, whereas the laser processing apparatus of the seventh embodiment is different from the first lens 104 in the fifth embodiment.
  • Reference numeral 104 denotes a convex lens, and the plane side is arranged to face the second lens 105 side.
  • the laser processing apparatus of the present embodiment has the same functions and effects as the laser processing apparatus of the fifth embodiment.
  • the second lens group is composed of one convex lens, that is, the second lens 105.
  • the second lens group 120 of the embodiment is configured by two lenses 121 and 122.
  • the second lens group 120 includes a biconcave lens 121 disposed on the convex lens 104 side as the first lens group and a biconcave lens 121 disposed adjacent to the biconcave lens 121. It is composed of a convex lens 122. The rear focal position of the entire second lens group 120 is positioned near the entrance pupil position of the objective lens 102.
  • the laser processing apparatus of the present embodiment can provide the same functions and effects as the laser processing apparatus of the seventh embodiment, and further increases the distance (distance) between the second lens group 120 and the objective lens 102. In the meantime, other observation systems and the like can be arranged, and the degree of freedom in design can be improved.
  • the first lens group is composed of one biconcave lens, that is, the first lens 104.
  • the first lens group 125 of the ninth embodiment is configured by two lenses 126 and 127. That is, as shown in FIG. 15, the first lens group 125 of the present embodiment has a convex portion with a laser light source. And a biconcave lens 127 disposed adjacent to the convex lens 126.
  • the second lens group according to the present embodiment includes one biconvex lens 128.
  • the light flux incident in the parallel light flux state regardless of the position of the first lens group 125 is always refracted in the same state and enters the second lens 128.
  • the laser light device of the present embodiment has the same functions and effects as the laser processing device of the fifth embodiment.
  • the technical scope of the present invention is not limited to the fifth to ninth embodiments.
  • the first lens group and the second lens group may be constituted by one lens as in the fifth embodiment, or may be constituted by one lens as in the seventh and eighth embodiments.
  • the above lens may be used.
  • each lens is not limited to its type, for example, a convex lens, a concave lens, or a biconvex lens, and may be designed by freely joining together.
  • the moving unit 106 is set so as to move the first lens group so as to satisfy the following expression.
  • I f I is a composite focal length of the first lens group and the second lens group.
  • the second lens group may be set so as to satisfy the following expression.
  • f2 is the focal length of the second lens group.
  • the entrance pupil position of the condensing optical system is often located in the condensing optical system, but by setting the second lens group to a positive power (convex lens), the entrance pupil position of the condensing optical system 103 is set in the optical system. Even if it exists, the rear focal position of the second lens group can be matched with the entrance pupil position of the condenser optical system 103.
  • fl is the focal length of the first lens group
  • f2 is the focal length of the second lens group.
  • the first lens group has negative power (concave lens) and the second lens group has positive power (convex lens).
  • the configuration can be made compact.
  • l ⁇ f2 / fl the first lens group can be easily configured. For this reason, it is possible to suppress the performance degradation that can be achieved by the power if possible at low cost. Since I f2 / fl I ⁇ 5, the optical system can be made compact.
  • the settings of the first lens group and the second lens group are not limited to fl ⁇ 0 and 1 ⁇ I f2 / fl I ⁇ 5.
  • the setting may be made so as to satisfy the following expression.
  • the focal lengths of both lens groups can be set to a positive focal length, and relaying can be performed with a simple configuration near the same magnification.
  • the moving means is automatically controlled by the control unit. However, based on the calculation result by the control unit, the moving means is operated to perform the first operation. You can move the lens group.
  • the optical system of the present invention may be used for an aberration correction optical system as shown in FIG. 16 to perform spherical aberration correction. That is, the aberration correction optical system 140 is an optical system that condenses a light beam from a light source (not shown), and a plurality of lenses 141, 142, and 143 that satisfy the following expression are exclusively disposed in the optical path so as to be able to be removed. RU
  • d is the distance from the entrance pupil position of the condenser optical system 103 including the objective lens 102 to the plurality of lenses 141, 142, and 143
  • 1 is the entrance pupil position of the condenser optical system 103.
  • f is the focal position of the plurality of lenses 141, 142, and 143
  • NA is the NA of the light source (NA as viewed from the condenser lens)
  • a is the a
  • Condensing This is the entrance pupil diameter of the optical system 103.
  • the light beam is in a divergent light state, and the plurality of lenses 141, 142, and 143 function as convex lenses.
  • the aberration correction optical system 140 configured as described above, even if a divergent light source is used to observe (collect) a portion of the wafer A with a different depth, the light amount is constant, and the light amount in the pupil plane is increased. Observation (condensing) with a constant distribution and a reduced amount of spherical aberration can be performed. In addition, it is not necessary to combine expensive objective lenses such as a correction ring objective lens, or to exchange glass or the like having different thicknesses as before.
  • a plurality of lenses 141, 142, and 143 which are convex lenses, are arranged in the divergent light beam.
  • a plurality of lenses 141, 142, 143 may be arranged.
  • the plurality of lenses 141, 142, and 143 may be concave lenses.
  • a plurality of lenses 141, 142, and 143 which are concave lenses, may be arranged in a parallel light beam.
  • a plurality of lenses 141, 142, 143 may be arranged after the parallel light beam is converted into convergent light by the negative lens 145.
  • the laser beam is focused on the wafer.
  • the laser beam is not limited to the wafer and may be focused on the medium.
  • the distance to be condensed is set to a distance of 50 m, 75 m, or 100 ⁇ m from the surface of the wafer. The force is not limited to these distances, and may be set arbitrarily.
  • the relative distance in the optical axis direction between the objective lens and the surface of the wafer was changed by moving the stage.
  • the present invention is not limited to this.
  • the objective lens may be changed by using a piezo element or the like.
  • the relative distance may be changed by moving.
  • the observation optical system described in the fifth embodiment is an example, and is configured by combining optical systems such as lenses as long as the distance from the lower surface of the objective lens to the surface of the wafer can be maintained at a predetermined distance. You can do it! /
  • the present invention includes the following.
  • a condensing optical system for condensing the laser light in the parallel light beam state into a medium; and a light beam, which extends along the optical axis direction of the parallel light beam in the parallel light beam between the parallel light beam means and the light condensing optical system.
  • a first lens group which is movably disposed and comprises one or more lenses;
  • a second lens group which is fixedly disposed in the parallel light flux between the first lens group and the condensing optical system, and includes one or more lenses;
  • Moving means for moving the first lens group in accordance with the refractive index of the medium on which the laser light is to be focused and the distance from the surface of the medium to the position on which the laser light is to be focused;
  • a laser processing apparatus wherein the second lens group has a rear focal point located at least near an entrance pupil position of the light-collecting optical system.
  • An observation optical system provided in association with the condensing optical system and maintaining a predetermined distance from the lower surface of the condensing optical system to the surface of the medium;
  • This observation optical system includes a focus detection unit or an autofocus mechanism. (Appendix 3)
  • the moving means moves the first lens group to a position satisfying the following expression.
  • the second lens group satisfies the following equation. f2> 0
  • the first lens group and the second lens group satisfy the following equation.
  • the first lens group and the second lens group satisfy the following equation.
  • the laser light was focused, the refractive index of the medium, and focused from the surface of the medium! /, Depending on the distance to the position, the following formula was satisfied in the convergent or divergent light flux of the focusing optical system.
  • Laser processing equipment with a laser focusing optical system in which multiple lenses that can be inserted and removed are exclusively inserted.
  • NA numerical aperture of light source (numerical aperture viewed from condensing lens)
  • a laser light source for emitting a laser beam parallel to the optical axis;
  • An optical system for condensing the laser beam into a medium;
  • the laser beam was condensed! /,
  • the refractive index of the medium, the beam was condensed from the surface of the medium! /,
  • a plurality of lenses satisfying the following equation were exclusively excluded in the laser beam.
  • a laser processing device that has a laser focusing optical system that can be inserted and removed.
  • the laser diverging point moving means is used in accordance with the condensed light !, the refractive index of the medium, and the distance from the surface of the medium to the position where the light is condensed. Since the laser divergence point is moved along the optical axis of the laser light, it is possible to minimize the amount of spherical aberration generated at different positions in the medium at different depths. Therefore, the laser light can be efficiently condensed to a desired depth of the medium, and the light condensing performance can be improved.
  • the laser beam can be efficiently focused at different depths in the medium while suppressing the occurrence of spherical aberration as much as possible.
  • Laser beam can be performed.
  • the first lens group depends on the refractive index of the medium to be focused and the distance from the surface of the medium to the position to be focused.
  • the position of the laser beam incident on the second lens group can be changed, that is, the light source position can be changed from the viewpoint of the condensing optical system.
  • the laser beam can be focused while minimizing the amount of light generation. Therefore, laser processing can be performed with high accuracy.
  • the second lens group whose rear focal point coincides with the entrance pupil position of the condenser optical system does not change the diameter of the light beam incident on the entrance pupil of the condenser optical system.

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Abstract

A laser beam collecting optical system is provided with a laser beam source for projecting laser beams; a beam collecting optical system arranged between the laser beam source and a medium, for collecting the laser beams in the medium; and a laser emitting point moving means, which can move a position of a laser emitting point of the laser beams along the optical axis of the laser beams, corresponding to a refraction factor of the medium wherein the laser beams are to be collected and a distance between the surface of the medium and a position whereupon the laser beams are to be collected.

Description

明 細 書  Specification
レーザ加工装置  Laser processing equipment
技術分野  Technical field
[0001] 本発明は、媒質中の異なる部分にレーザ光を集光させるレーザ集光光学系及びレ 一ザ加工装置に関する。  The present invention relates to a laser focusing optical system that focuses laser light on different portions in a medium and a laser processing device.
また、本発明は、光学系の瞳面内に入射する光量、光量分布を一定にしたまま光 源位置を変えることができるレーザ加工装置に関する。特に、本発明は、媒質中の深 さが異なる部分にレーザ光を集光させることができる最適なレーザ加工装置、若しく は、集光位置を変えるのに適したレーザ加工装置に関する。  Further, the present invention relates to a laser processing apparatus capable of changing a light source position while keeping a light amount incident on a pupil plane of an optical system and a light amount distribution constant. In particular, the present invention relates to an optimum laser processing apparatus capable of condensing laser light on a portion having a different depth in a medium, or a laser processing apparatus suitable for changing a condensing position.
本出願は、特願 2004— 132995号と、特願 2004— 132997号とを基礎出願とし、 その内容を取り込むものとする。  This application is based on Japanese Patent Application No. 2004-132995 and Japanese Patent Application No. 2004-132997, and incorporates the contents thereof.
背景技術  Background art
[0002] 現在、様々な分野でレーザ光が応用されており、レーザ光を利用した各種装置が 開発されている。例えば、その 1つとして半導体ウェハやガラス等の被カ卩ェ対象物を 、レーザ光を利用して切断する加工装置が知られている。この加工装置は、レーザ光 源力 のレーザ光を集光光学系によって集光させることにより、媒質に改質層等を発 生させて切断加工を行うものである。また、切断を行う際、被加工対象物の厚みは様 々であるので常に同じ深さに集光させるのではなぐ被カ卩ェ対象物の厚みに応じて 異なった深さに集光させることが必要とされている。即ち、媒質中の異なる深さ部分 に集光させた 、と 、う要求がある。  [0002] At present, laser light is applied in various fields, and various devices using laser light are being developed. For example, as one of them, a processing apparatus that cuts an object to be cut such as a semiconductor wafer or glass by using a laser beam is known. This processing apparatus performs a cutting process by generating a modified layer or the like in a medium by condensing a laser beam having a laser beam source power by a condensing optical system. Also, when cutting, the thickness of the object to be processed varies, so it is not always necessary to focus the light at the same depth. Is needed. That is, there is a demand that the light is focused at different depths in the medium.
しかしながら、異なる厚み (深さ）間で球面収差量が異なるので、集光性能が変化（ 劣化)する可能性があった。  However, since the amount of spherical aberration differs between different thicknesses (depths), there is a possibility that the light-collecting performance may change (degrade).
[0003] 上述のように、媒質中の異なった深さ部分に集光させたいという要求がある力 その 場合、球面収差の発生を招いてしまう。例えば、生物分野において、顕微鏡標本を 作製する場合には、ほとんどの場合、スライドガラスの上に試料を置き、その上にカバ 一ガラスを載せて封入するカバーガラス付きの標本が一般的である力 カバーガラス の厚みの異なる標本を顕微鏡により観察するような場合に、上述した球面収差が発 生してしまう。また、 LCD用のガラスには厚みの異なるものがあり、基板越しに観察す る場合にも球面収差が発生してしまう。また、異なる厚み (深さ）間で球面収差量が異 なると、集光性能が変化 (劣化)する可能性があった。 [0003] As described above, there is a demand for condensing light at different depths in a medium. In such a case, spherical aberration is generated. For example, in the field of biology, when preparing a microscope specimen, in most cases, a specimen with a cover glass in which a sample is placed on a slide glass and a cover glass is placed on top of it and sealed is generally used. When observing specimens with different cover glass thicknesses under a microscope, the above-mentioned spherical aberration occurs. Will be born. In addition, there are LCD glasses having different thicknesses, and spherical aberration is generated even when viewing through a substrate. Also, if the amount of spherical aberration differs between different thicknesses (depths), the light condensing performance may change (degrade).
[0004] そこで、従来より、球面収差の補正を行って集光性能の変化を抑えながら上述した ような厚みの異なる部分に集光させるために、様々な技術が採用されている。 [0004] Therefore, conventionally, various techniques have been employed to correct spherical aberration and condense light to portions having different thicknesses as described above while suppressing a change in light condensing performance.
そのうちの 1つとして、例えば、厚みの異なる平行平板ガラスを対物レンズ等の集光 光学系の先端に着脱可能に配置するものが知られている。  As one of them, for example, one in which parallel plate glasses having different thicknesses are detachably arranged at the tip of a condensing optical system such as an objective lens is known.
また、例えば、倍率が 40倍程度、開口数 NA (Numerical Aperture)が 0. 93の超広 視野の範囲にわたって諸収差が良好に補正され、カバーガラス厚の変動による性能 劣化も少ない顕微鏡用補正環付き対物レンズが知られている（例えば、特許文献 1 参照)。  In addition, for example, a microscope correction ring with a magnification of about 40 times and a numerical aperture NA (Numerical Aperture) of 0.93 is excellently corrected over an ultra-wide field of view, and there is little deterioration in performance due to variations in cover glass thickness. 2. Description of the Related Art An attached objective lens is known (for example, see Patent Document 1).
更に、無限遠 (No Power Lens)の球面収差補正光学系を光軸方向に移動させて球 面収差を補正する光学系も知られている（例えば、特許文献 2参照)。  Further, an optical system that corrects spherical aberration by moving an optical system for correcting spherical aberration at infinity (No Power Lens) in the optical axis direction is also known (for example, see Patent Document 2).
更には、図 20に示すように、対物レンズ 230と光源 231との間に球面収差補正レン ズ 232を配置し、この球面収差補正レンズ 232を光軸に沿って移動させることにより 球面収差を補正する顕微鏡装置が知られて ヽる (例えば、特許文献 3参照)。  Further, as shown in FIG. 20, a spherical aberration correction lens 232 is disposed between the objective lens 230 and the light source 231 and the spherical aberration is corrected by moving the spherical aberration correction lens 232 along the optical axis. There is known a microscope device that performs the following (for example, see Patent Document 3).
特許文献 1 :特開平 5— 119263号公報（図 1等）  Patent Document 1: JP-A-5-119263 (Fig. 1 etc.)
特許文献 2 :特開 2003— 175497号公報（図 1等）  Patent Document 2: Japanese Patent Application Laid-Open No. 2003-175497 (FIG. 1 etc.)
特許文献 3：特開 2001— 83428号公報（図 1等）  Patent Document 3: Japanese Patent Application Laid-Open No. 2001-83428 (FIG. 1 etc.)
[0005] ところで、上述した球面収差補正のうち、平行平板ガラスを利用したものは、平行平 板ガラスの傾き等による性能劣化が大きい。そのため、平行平板を保持する枠に高 精度が要求され、また、平行平板の枠への固定も精度が必要になることから高価に なる。また、小さい WD (Work Distance)の中で、手動により交換を行う必要があり、こ れが非常に手間の力かる作業であった。更に、連続可変を行うことが難し力つた。 また、特許文献 1に記載の補正環対物レンズでは、高精度であるため価格が高ぐ 低コストィ匕を図ることができない。また、集光位置に応じて自動で球面収差量を調整 することが難しく自動化への対応が困難なものである。 [0005] Among the above-mentioned spherical aberration corrections, those using a parallel plate glass have a large performance degradation due to the inclination of the parallel plate glass and the like. For this reason, high precision is required for the frame that holds the parallel plate, and the fixing of the parallel plate to the frame also requires high precision, which is expensive. In addition, manual replacement was required within a small WD (Work Distance), which was a very laborious task. Furthermore, it was difficult to make continuous variable. Further, the correction ring objective lens described in Patent Document 1 has high accuracy and is expensive, so that it is not possible to achieve low cost. Also, it is difficult to automatically adjust the amount of spherical aberration according to the focusing position, and it is difficult to respond to automation.
また、特許文献 2に記載の光学系では、合成焦点距離を無限遠のレンズで補正す るため、球面収差を補正した場合でも集光位置は変化しない。媒質中の異なった部 分に集光しょうとすると必ず WDが変わり、 WD—定の下での収差補正を行うことがで きな力つた。また、ビームエキスパンダ以外に球面収差補正光学系が必要となるので 、構成が複雑で部品点数が多くなり、低コストィ匕を図ることが困難であった。 In the optical system described in Patent Document 2, the combined focal length is corrected by a lens at infinity. Therefore, even when the spherical aberration is corrected, the focusing position does not change. When trying to focus light on different parts of the medium, the WD always changed, and it was impossible to correct aberrations under the constant WD. In addition, since a spherical aberration correcting optical system is required in addition to the beam expander, the configuration is complicated, the number of parts is increased, and it has been difficult to reduce the cost.
[0006] また、特許文献 3に記載の顕微鏡装置では、図 20に示すように、球面収差補正レ ンズ 232を光軸方向に移動させることにより、球面収差の補正を行うことができるが、 球面収差補正レンズ 232の移動に伴い、対物レンズ 230に入射する光束径が変化し てしまう。 [0006] Further, in the microscope device described in Patent Document 3, as shown in FIG. 20, the spherical aberration can be corrected by moving the spherical aberration correction lens 232 in the optical axis direction. With the movement of the aberration correction lens 232, the diameter of the light beam incident on the objective lens 230 changes.
即ち、光束の広がりが変化してしまう。そのため、図 21に示すように、光量が変化し てしまい、標本面上での明るさが変化してしまう。ここで、画像取得手段がある場合に は、画像の明るさを検出し、明るさによって光源のパワーを変化させる。画像側で明 るさをコントロールする等により、明るさを一定にできるが、装置構成が複雑になる等 の問題がある。  That is, the spread of the light beam changes. Therefore, as shown in FIG. 21, the amount of light changes, and the brightness on the sample surface changes. Here, if there is an image acquisition unit, the brightness of the image is detected, and the power of the light source is changed according to the brightness. The brightness can be made constant by controlling the brightness on the image side, but there is a problem that the device configuration becomes complicated.
また、瞳面内での光量分布がある場合には、この光量分布も変化する恐れがあつ た。このような光量分布の変化により、集光性能が変化するという問題があった。更に 、画像取得手段からの電気信号に基づいて球面収差補正レンズを移動するため、時 間のかかるものであった。  Further, when there is a light amount distribution in the pupil plane, there is a possibility that this light amount distribution may also change. There is a problem that the light collecting performance changes due to such a change in the light amount distribution. Further, it takes time to move the spherical aberration correction lens based on the electric signal from the image acquisition means.
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0007] 本発明は、上記事情に鑑みてなされたもので、シンプルな構成で手間をかけること なく容易に球面収差補正を行うことができるレーザ集光光学系及びレーザ加工装置 の提供を目的とする。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a laser focusing optical system and a laser processing apparatus that can easily perform spherical aberration correction with a simple configuration without trouble. I do.
課題を解決するための手段  Means for solving the problem
[0008] 上記課題を達成するために、本発明は、以下の手段を採用した。 [0008] In order to achieve the above object, the present invention employs the following solutions.
すなわち、本発明のレーザ集光光学系は、レーザ光を出射するレーザ光源と;この レーザ光源と媒質との間に配されて前記レーザ光を媒質中に集光させる集光光学系 と;前記レーザ光のレーザ発散点の位置を、レーザ光を集光させたい前記媒質の屈 折率及び前記媒質の表面から集光させた!/、位置までの距離に応じて、前記レーザ 光の光軸上に沿って移動可能なレーザ発散点移動手段と；を備えて!/、る。 That is, a laser condensing optical system of the present invention comprises: a laser light source for emitting laser light; a condensing optical system disposed between the laser light source and a medium for condensing the laser light in the medium; The position of the laser divergence point of the laser light was determined according to the refractive index of the medium to which the laser light was to be focused and the laser light from the surface of the medium! / According to the distance to the position. Means for moving the laser divergence point along the optical axis of the light.
[0009] このレーザ集光光学系によれば、集光光学系によりレーザ光源から出射されたレー ザ光を媒質中に集光させることができる。この際、レーザ光は、集光光学系に発散光 状態 (非平行光束状態)で入射される。つまり、レーザ光源から発散光状態で出射、 又はレーザ光源力 平行光束状態で出射された後に各種レンズにより発散光状態に 変換されて集光光学系に入射する。このようにレーザ光が発散光状態になった点を 発散点としている。また、レーザ光を集光させる際に、集光させたい媒質の屈折率及 び媒質の表面から集光させた 、位置までの距離に応じて、レーザ発散点移動手段 によりレーザ発散点をレーザ光の光軸上に沿って移動させるので、媒質中の深さが 異なる箇所にレーザ光を集光させたとしても、それぞれの位置において球面収差の 発生量を極力抑えることができる。従って、レーザ光を所望する媒質の深さに効率良 く集光させることができ、集光性能の向上を図ることができる。  According to the laser condensing optical system, the laser light emitted from the laser light source by the condensing optical system can be condensed in a medium. At this time, the laser light is incident on the focusing optical system in a divergent light state (non-parallel light beam state). That is, the light is emitted from the laser light source in a divergent light state, or emitted in a parallel light flux state by the laser light source, converted into a divergent light state by various lenses, and is incident on the condensing optical system. The point at which the laser light enters the diverging light state is referred to as the diverging point. When condensing the laser light, the laser divergence point moving means sets the laser divergence point by the laser divergence point moving means according to the refractive index of the medium to be condensed and the distance to the position condensed from the surface of the medium. Since the laser beam is moved along the optical axis, even if the laser light is focused on the medium at different depths, the amount of spherical aberration generated at each position can be minimized. Therefore, the laser light can be efficiently condensed to a desired depth of the medium, and the light condensing performance can be improved.
特に、レーザ発散点を移動させるだけであるので、従来のように手間をかけることな ぐ容易に球面収差補正を行うことができる。また、従来の補正環対物レンズ等のよう に特別な光学系を備える必要がないので、構成のシンプルィ匕を図ることができると共 に低コストィ匕を図ることができる。更に、レーザ発散点を移動させるだけであるので、 連続可変を行い易ぐ自動化に対応し易い。  In particular, since the laser divergence point is merely moved, spherical aberration correction can be easily performed without any trouble as in the related art. In addition, since it is not necessary to provide a special optical system unlike the conventional correction ring objective lens, the configuration can be simplified and the cost can be reduced. Furthermore, since it is only necessary to move the laser divergence point, it is easy to cope with automation that can easily be continuously varied.
[0010] 前記レーザ発散点移動手段が、予め測定された前記集光光学系の波面データに 基づ 、てレーザ発散点の位置を設定してもよ 、。  [0010] The laser divergence point moving means may set the position of the laser divergence point based on the wavefront data of the condensing optical system measured in advance.
[0011] この場合、レーザ発散点移動手段が、予め測定された集光光学系の波面データ、 例えば、集光光学系を構成している一部である対物レンズの波面データや、集光光 学系全体の波面データを考慮してレーザ発散点の位置を設定するので、レーザ光の 集光性能をさらに向上させることができる。  [0011] In this case, the laser divergence point moving means may measure the wavefront data of the condensing optical system measured in advance, for example, the wavefront data of the objective lens which is a part of the condensing optical system, or the condensed light. Since the position of the laser divergence point is set in consideration of the wavefront data of the entire system, the laser light focusing performance can be further improved.
[0012] 前記集光光学系に連携して設けられ、集光光学系の下面から前記媒質の表面ま での距離を所定の距離に維持する観察光学系を備え、この観察光学系が、フォー力 ス検出手段又はオートフォーカス機構を備えてもよ!、。  [0012] An observation optical system is provided in cooperation with the condensing optical system and maintains a predetermined distance from the lower surface of the condensing optical system to the surface of the medium. A force detection means or an auto-focus mechanism may be provided!
[0013] この場合、観察光学系により集光光学系の下面から媒質の表面までの距離を所定 の距離に維持できるので、例えば、集光光学系と媒質との水平方方向の相対的な移 動、即ち、走査を行ったとしても、所望する深さに集光されたレーザ光を同一位置に 維持しながら走査を行うことができる。従って、異なる深さに球面収差量の発生を極 力抑えながら、媒質全体に亘つてレーザ光を集光させることができる。 In this case, the distance from the lower surface of the light collecting optical system to the surface of the medium can be maintained at a predetermined distance by the observation optical system. For example, the relative movement of the light collecting optical system and the medium in the horizontal direction can be maintained. Even if the scanning, that is, the scanning is performed, it is possible to perform the scanning while maintaining the laser beam condensed to a desired depth at the same position. Therefore, it is possible to condense laser light over the entire medium while minimizing the generation of spherical aberration at different depths.
[0014] 前記集光光学系と前記媒質の表面との光軸方向の相対的な距離が一定であって ちょい。  [0014] The relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium is constant.
[0015] この場合、レーザ光を集光させたい媒質深さが変化した場合でも、集光光学系と媒 質の表面との光軸方向の相対的な距離、即ち、 WDが一定になるよう設定されている ので、構成が簡単になる。  [0015] In this case, even when the depth of the medium on which the laser light is to be focused changes, the relative distance in the optical axis direction between the focusing optical system and the surface of the medium, that is, the WD is kept constant. Because it is set, the configuration is simplified.
[0016] 上記レーザ集光光学系を備えたレーザ加工装置を採用してもよい。  [0016] A laser processing apparatus provided with the above laser focusing optical system may be employed.
[0017] この場合、媒質中の異なる各深さに、球面収差の発生を極力抑えた状態でレーザ 光の集光を効率良く行えるので、正確なレーザ加工を行うことができ、ウェハ等を高 精度に切断することが可能である。  [0017] In this case, since laser light can be efficiently condensed at different depths in the medium while spherical aberration is minimized, accurate laser processing can be performed, and the height of the wafer or the like can be increased. It is possible to cut with precision.
[0018] 本発明のレーザ加工装置の第 1の態様は、レーザ光を射出するレーザ光源と;この レーザ光源から射出された前記レーザ光の光束を平行光束にする平行光束手段と； 前記平行光束状態の前記レーザ光を媒質中に集光させる集光光学系と;前記平行 光束手段と前記集光光学系との間の前記平行光束中に、この平行光束の光軸方向 に沿って移動可能に配されて、 1枚以上のレンズにより構成された第 1レンズ群と;こ の第 1レンズ群と前記集光光学系との間の前記平行光束中に固定された状態で配さ れて、 1枚以上のレンズにより構成された第 2レンズ群と;前記レーザ光を集光させた V、前記媒質の屈折率及び媒質表面から集光させた!/、位置までの距離に応じて、前 記第 1のレンズ群を移動させる移動手段と;を備え、前記第 2レンズ群が、後側焦点 位置が前記集光光学系の入射瞳位置の少なくとも近傍に配されている。  [0018] A first aspect of the laser processing apparatus of the present invention is a laser light source for emitting laser light; parallel light beam means for converting the light beam of the laser light emitted from the laser light source to a parallel light beam; A condensing optical system for condensing the laser light in a state in a medium; movable in the parallel light beam between the parallel light beam means and the light condensing optical system along the optical axis direction of the parallel light beam A first lens group composed of one or more lenses; and a first lens group fixedly arranged in the parallel light flux between the first lens group and the condensing optical system. A second lens group composed of one or more lenses; and V, the laser beam is focused, the refractive index of the medium and the laser beam focused from the surface of the medium! /, Depending on the distance to the position. Moving means for moving the first lens group; wherein the second lens group is Point position is arranged at least near the entrance pupil position of the condensing optical system.
[0019] このレーザ加工装置によれば、レーザ光源力 射出されたレーザ光が、平行光束 手段により平行光束に変換され、第 1レンズ群及び第 2レンズ群でそれぞれ屈折した 後、集光光学系に入射して媒質中に集光される。この際、移動手段により、第 1レン ズ群を光軸方向に移動させることで、光源位置を光軸方向に移動させることができる 。即ち、第 1レンズ群を移動させることで、第 2レンズ群カゝら見た光源位置を変えること ができ、更には、前記集光光学系力も見た実質的な光源位置の変更が行える。 集光させた!/、媒質の屈折率及び媒質表面から集光させた!/、位置までの距離に応 じて、第 1レンズ群を移動させることで、前記集光光学系カゝら見た光源位置を変更で き、所望する位置 (深さ)に球面収差の発生量を極力抑えた状態でレーザ光を集光さ せることができる。従って、レーザ力卩ェを高精度に行うことができ、例えば、ウェハ等を より正確に切断することができる。 According to this laser processing apparatus, the emitted laser light is converted into a parallel light beam by the parallel light beam means and refracted by the first lens group and the second lens group, respectively. And is collected in the medium. At this time, by moving the first lens group in the optical axis direction by the moving means, the light source position can be moved in the optical axis direction. That is, by moving the first lens group, the position of the light source viewed from the second lens group can be changed, and further, the position of the light source can be substantially changed while also looking at the power of the condensing optical system. Condensed! /, Condensed from the medium's refractive index and the surface of the medium! / By moving the first lens group according to the distance to the position, The position of the light source can be changed, and the laser beam can be focused at a desired position (depth) while minimizing the amount of spherical aberration generated. Therefore, the laser beam can be cut with high precision, and for example, a wafer or the like can be cut more accurately.
また、第 2レンズ群の後側焦点位置と集光光学系の入射瞳位置とがー致するように 配置されており、第 1レンズ群が光軸に沿って移動した場合でも、第 1レンズ群に入 射した平行光束は第 1レンズ群の位置によらず、集光光学系の入射瞳位置で常に同 じ光束径となり、集光光学系でけられることなく集光させる。即ち、集光位置での光量 変化を小さくすることが可能であり、集光光学系の入射瞳面での光量分布が変化し ないので、集光性能の変化を抑えることができる。  Also, the rear focal position of the second lens group and the entrance pupil position of the condensing optical system are arranged so as to match, so that even if the first lens group moves along the optical axis, the first lens group is moved. The parallel luminous flux incident on the group always has the same luminous flux diameter at the entrance pupil position of the converging optical system regardless of the position of the first lens group, and is condensed without being shaken by the converging optical system. That is, it is possible to reduce the change in the light amount at the light condensing position, and since the light amount distribution on the entrance pupil plane of the light collecting optical system does not change, the change in the light condensing performance can be suppressed.
更に、第 1レンズ群を移動させるだけで光源位置の変更が行えるので、従来のよう に集光光学系やステージ等を光軸方向に動かす必要がない。従って、構成のシンプ ルイ匕を図ることができ、手間をかけることなく容易に球面収差補正を行うことができる。 また、従来の補正環対物レンズ等のように、特別な光学系を備える必要がないことか らも、構成のシンプルィ匕が図れ、低コストィ匕を図ることができる。  Furthermore, since the position of the light source can be changed only by moving the first lens group, there is no need to move the converging optical system, the stage, and the like in the optical axis direction as in the related art. Accordingly, the configuration can be simplified, and the spherical aberration can be easily corrected without any trouble. Further, unlike the conventional correction ring objective lens, it is not necessary to provide a special optical system, so that the configuration can be simplified and the cost can be reduced.
[0020] 前記集光光学系に連係して設けられ、集光光学系の下面から前記媒質の表面ま での距離を所定の距離に維持する観察光学系を備え、この観察光学系が、フォー力 ス検出手段又はオートフォーカス機構を備えてもよ!、。  [0020] An observation optical system is provided in association with the condensing optical system and maintains a predetermined distance from the lower surface of the condensing optical system to the surface of the medium. A force detection means or an auto-focus mechanism may be provided!
[0021] この場合、観察光学系により集光光学系の下面から媒質の表面までの距離を所定 の距離に維持できるので、例えば、集光光学系と媒質との水平方向の相対的な移動 、即ち、走査を行う際に、媒質表面からの深さを所望する深さに正確に制御すること ができる。  In this case, since the distance from the lower surface of the light collecting optical system to the surface of the medium can be maintained at a predetermined distance by the observation optical system, for example, the horizontal relative movement between the light collecting optical system and the medium That is, when scanning, the depth from the medium surface can be accurately controlled to a desired depth.
[0022] 前記集光光学系と前記媒質の表面との光軸方向の相対的な距離が一定であって ちょい。  [0022] The relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium may be constant.
[0023] この場合、集光光学系と媒質の表面との光軸方向の相対的な距離、即ち、 WDが 一定になるように設定されて 、るので、よりオートフォーカス機構を簡単に構成するこ とが可能となり、安価に構成できる。 [0024] 前記第 1レンズ群と前記第 2レンズ群との合焦距離を I f Iとした場合、前記移動手 段が、前記第 1レンズ群を、下記式を満たす位置に移動させてもよい。 In this case, the relative distance between the light-collecting optical system and the surface of the medium in the optical axis direction, that is, the WD is set to be constant, so that the autofocus mechanism can be configured more easily. This is possible and can be configured at low cost. [0024] If the focusing distance between the first lens group and the second lens group is I f I, the moving means may move the first lens group to a position satisfying the following equation. Good.
1/ I f I <o. 01  1 / I f I <o. 01
[0025] 前記第 2レンズ群の焦点距離を f2とした場合、前記第 2レンズ群が、下記式を満た してちよい。  When the focal length of the second lens group is f2, the second lens group may satisfy the following expression.
f2 >0  f2> 0
[0026] 前記第 1レンズ群の焦点距離を fl、前記第 2レンズ群の焦点距離を f2とした場合、 前記第 1レンズ群及び前記第 2レンズ群が、下記式を満たしてもよ!/、。  When the focal length of the first lens group is fl and the focal length of the second lens group is f2, the first lens group and the second lens group may satisfy the following equation! / ,.
fl < 0  fl <0
かつ、 1≤ I Ϊ1/Ϊ2 I ≤5  And 1≤ I Ϊ1 / Ϊ2 I ≤5
[0027] 前記第 1レンズ群の焦点距離を fl、前記第 2レンズ群の焦点距離を f2とした場合、 前記第 1レンズ群及び前記第 2レンズ群が、下記式を満たしてもよ!/、。 When the focal length of the first lens group is fl and the focal length of the second lens group is f2, the first lens group and the second lens group may satisfy the following equation! / ,.
fl >0  fl> 0
かつ、 0. 5≤ I fl/f2 I ≤2  And 0.5 ≤ I fl / f2 I ≤2
[0028] 本発明のレーザ加工装置の第 2の態様は、レーザ光を射出するレーザ光源と;前 記レーザ光を媒質中に集光させる集光光学系と；を含み、前記レーザ光を集光させ たい媒質の屈折率、媒質の表面から集光させたい位置までの距離に応じて、前記集 光光学系の収束又は発散光束中に下記式を満足する複数のレンズを排他で揷脱可 能に配置したレーザ集光光学系を有する。 [0028] A second aspect of the laser processing apparatus of the present invention includes a laser light source for emitting laser light; and a condensing optical system for condensing the laser light in a medium, and collects the laser light. Depending on the refractive index of the medium to be lighted and the distance from the surface of the medium to the position to be condensed, a plurality of lenses satisfying the following formula can be exclusively excluded during the convergence or divergence of the light collection optical system. It has a laser condensing optical system which is arranged in a function.
2 (d2+l X f-l X d) NA=f X a 2 (d 2 + l X fl X d) NA = f X a
ただし、 d；集光光学系の入射瞳位置力 複数のレンズまでの距離  However, d: the position of the entrance pupil of the condensing optical system Distance to multiple lenses
1 ;集光光学系の入射瞳位置から光源位置までの距離  1: Distance from the entrance pupil position of the condensing optical system to the light source position
f；複数のレンズの焦点位置  f; focal positions of multiple lenses
NA；光源の NA (集光レンズから見た NA)  NA; NA of light source (NA viewed from condensing lens)
a ;集光光学系の入射瞳径  a; entrance pupil diameter of condensing optical system
[0029] 本発明のレーザ加工装置の第 3の態様は、光軸に平行なレーザ光束を射出するレ 一ザ光源と；前記レーザ光束を媒質中に集光させる光学系と；を含み、前記レーザ光 束を集光させた!/ヽ媒質の屈折率、媒質の表面から集光させた！/ヽ位置までの距離に 応じて、レーザ光束中に下記式を満足する複数のレンズを排他で挿脱可能に配置し たレーザ集光光学系を有する。 [0029] A third aspect of the laser processing apparatus of the present invention includes a laser light source that emits a laser beam parallel to an optical axis; and an optical system that focuses the laser beam on a medium. Laser beam was focused! / ヽ Refractive index of the medium, focused from the surface of the medium! / ヽ distance to the position Accordingly, there is provided a laser focusing optical system in which a plurality of lenses satisfying the following expression are exclusively and removably arranged in a laser beam.
b (f -d) /f = a  b (f -d) / f = a
ただし、 b ;光源力 の平行光束径  Where b is the collimated beam diameter of the light source power
d ;集光光学系の入射瞳位置カゝら複数のレンズまでの距離 f；複数のレンズの焦点位置  d; distance from the entrance pupil position of the condensing optical system to a plurality of lenses f; focal positions of a plurality of lenses
a ;集光光学系の入射瞳径  a; entrance pupil diameter of condensing optical system
発明の効果  The invention's effect
[0030] 本発明に係るレーザ集光光学系によれば、集光させた!/、媒質の屈折率及び媒質 の表面から集光させたい位置までの距離に応じて、レーザ発散点移動手段によりレ 一ザ発散点をレーザ光の光軸上に沿って移動させるので、媒質中の深さが異なるそ れぞれの位置で、球面収差の発生量を極力抑えることができる。従って、レーザ光を 所望する媒質の深さに効率良く集光させることができ、集光性能の向上を図ることが できる。  According to the laser condensing optical system according to the present invention, the laser diverging point moving means is used in accordance with the condensed light !, the refractive index of the medium, and the distance from the surface of the medium to the position where the light is condensed. Since the laser divergence point is moved along the optical axis of the laser light, it is possible to minimize the amount of spherical aberration generated at different positions in the medium at different depths. Therefore, the laser light can be efficiently condensed to a desired depth of the medium, and the light condensing performance can be improved.
特に、レーザ発散点を移動させるだけであるので、従来のように手間をかけることな ぐ容易に球面収差補正を行うことができると共に特別な光学系を備える必要がない ので、構成のシンプルィ匕を図ることができ、低コストィ匕を図ることができる。  In particular, since only the laser divergence point is moved, spherical aberration correction can be easily performed without any trouble as in the related art, and there is no need to provide a special optical system. Therefore, low cost dangling can be achieved.
また、上記レーザ集光光学系を備えたレーザ加工装置によれば、媒質中の異なる 各深さに、球面収差の発生を極力抑えた状態でレーザ光の集光を効率良く行えるの で、正確なレーザ力卩ェを行うことができる。  Further, according to the laser processing apparatus provided with the above laser focusing optical system, the laser beam can be efficiently focused at different depths in the medium while suppressing the occurrence of spherical aberration as much as possible. Laser beam can be performed.
[0031] 本発明に係るレーザ加工装置の第 1〜第 3の態様によれば、集光させたい媒質の 屈折率及び媒質表面から集光させたい位置までの距離に応じて、第 1レンズ群を移 動させることで、第 2レンズ群に入射するレーザ光の位置を変更できる、即ち、集光光 学系から見た光源位置の変更が行えるので、所望する位置 (深さ）に球面収差の発 生量を極力抑えた状態でレーザ光を集光させることができる。従って、レーザ加工を 高精度に行うことができる。 [0031] According to the first to third aspects of the laser processing apparatus according to the present invention, the first lens group depends on the refractive index of the medium to be focused and the distance from the surface of the medium to the position to be focused. By moving the laser beam, the position of the laser beam incident on the second lens group can be changed, that is, the light source position can be changed from the viewpoint of the condensing optical system, so that the spherical aberration can be changed to a desired position (depth). The laser beam can be focused while minimizing the amount of light generation. Therefore, laser processing can be performed with high accuracy.
また、後側焦点位置が集光光学系の入射瞳位置に一致した第 2レンズ群により、集 光光学系の入射瞳に入射する光束径を変化させることがないので、入射光量や、瞳 面内での光量分布を一定にすることができ、集光性能の変化を抑えることができる。 更に、第 1レンズ群を移動させるだけで、光源位置の変更が行えるので、構成のシ ンプルイ匕を図ることができ、手間をかけることなく容易に球面収差補正を行うことがで きる。 In addition, the second lens group whose rear focal position matches the entrance pupil position of the condenser optical system does not change the diameter of the light beam incident on the entrance pupil of the condenser optical system. The light amount distribution in the plane can be made constant, and the change in the light collecting performance can be suppressed. Further, since the position of the light source can be changed only by moving the first lens group, the configuration can be simplified, and spherical aberration can be easily corrected without any trouble.
図面の簡単な説明 Brief Description of Drawings
[図 1]本発明に係るレーザ加工装置及びレーザ集光光学系の第 1実施形態を示す構 成図である。 FIG. 1 is a configuration diagram showing a first embodiment of a laser processing apparatus and a laser focusing optical system according to the present invention.
[図 2]同レーザ集光光学系により、レーザ光をウェハの表面力 深さの異なる位置に 照射する場合のフローチャートの一例である。  FIG. 2 is an example of a flowchart in a case where laser light is applied to positions of the wafer having different surface forces and depths by the same laser focusing optical system.
[図 3]集光光学系の波面データを考慮に入れて、同レーザ集光光学系によりレーザ 光を照射する場合の一例である。  FIG. 3 is an example of a case where laser light is irradiated by the laser condensing optical system in consideration of wavefront data of the condensing optical system.
[図 4]本発明に係るレーザ集光光学系の第 2実施形態を示す構成図である。  FIG. 4 is a configuration diagram showing a second embodiment of the laser focusing optical system according to the present invention.
[図 5]同レーザ集光光学系により、レーザ光をウェハの表面力 深さの異なる位置に 照射する場合のフローチャートの一例である。  FIG. 5 is an example of a flowchart in the case where laser light is applied to positions of the wafer having different surface forces and depths by the same laser focusing optical system.
[図 6]本発明に係るレーザ集光光学系の第 3実施形態を示す図であって、レーザ光 をウェハの表面力 深さの異なる位置に照射する場合のフローチャートの一例である  FIG. 6 is a view showing a third embodiment of the laser condensing optical system according to the present invention, and is an example of a flowchart in a case where laser light is applied to positions on the wafer having different surface forces and depths.
[図 7]同フローチャートにより、レーザ光をウェハの表面力 深さの異なる位置に照射 させた状態を示す図である。 FIG. 7 is a view showing a state where laser light is applied to positions of the wafer having different surface force depths according to the flowchart.
[図 8]本発明に係るレーザ集光光学系の第 4実施形態を示す構成図である。  FIG. 8 is a configuration diagram showing a fourth embodiment of the laser focusing optical system according to the present invention.
[図 9]同レーザ集光光学系により、レーザ光をウェハの表面力 深さの異なる位置に 照射する場合のフローチャートの一例である。  FIG. 9 is an example of a flowchart in a case where laser light is applied to positions of the wafer having different surface forces and depths by the same laser focusing optical system.
[図 10]本発明に係るレーザ加工装置の第 5実施形態を示す構成図である。  FIG. 10 is a configuration diagram showing a fifth embodiment of the laser processing apparatus according to the present invention.
[図 11]同レーザ加工装置により、レーザ光をウェハ内の所望する深さに集光させる場 合のフローチャートの一例である。  FIG. 11 is an example of a flowchart in a case where a laser beam is focused to a desired depth in a wafer by the laser processing apparatus.
[図 12]本発明に係るレーザ加工装置の第 6実施形態を説明するフローチャートであ つて、 WD—定のままレーザ光をウェハ内の所望する深さに集光させる場合のフロー チャートの一例である。 圆 13]本発明に係るレーザ加工装置の第 7実施形態を示す構成図である。 FIG. 12 is a flowchart illustrating a laser processing apparatus according to a sixth embodiment of the present invention, and is an example of a flow chart in a case where laser light is focused to a desired depth in a wafer while keeping the WD constant. is there. [13] FIG. 13 is a configuration diagram showing a seventh embodiment of the laser processing apparatus according to the present invention.
圆 14]本発明に係るレーザ加工装置の第 8実施形態を示す構成図である。 [14] FIG. 14 is a configuration diagram showing an eighth embodiment of the laser processing apparatus according to the present invention.
圆 15]本発明に係るレーザ加工装置の第 9実施形態を示す構成図である。 [15] FIG. 15 is a configuration diagram showing a ninth embodiment of the laser processing apparatus according to the present invention.
圆 16]発散光束中に複数の凸レンズを揷脱可能に配したレーザ加工装置を示す図 である。 [16] Fig. 16 is a diagram showing a laser processing apparatus in which a plurality of convex lenses are arranged so as to be able to be removed from a divergent light beam.
圆 17]収束光束中に複数の凸レンズを揷脱可能に配したレーザ加工装置を示す図 である。 [17] FIG. 17 is a view showing a laser processing apparatus in which a plurality of convex lenses are arranged so as to be able to be removed from a convergent light beam.
圆 18]平行光束中に複数の凹レンズを揷脱可能に配したレーザ加工装置を示す図 である。 [18] FIG. 18 is a diagram showing a laser processing apparatus in which a plurality of concave lenses are arranged in a parallel light beam so as to be detachable.
[図 19]平行光束を凸レンズで収束光に変換し、この収束光中に複数の凹レンズを揷 脱可能に配したレーザ加工装置を示す図である。  FIG. 19 is a diagram showing a laser processing apparatus in which a parallel light beam is converted into convergent light by a convex lens, and a plurality of concave lenses are removably arranged in the convergent light.
圆 20]従来の球面収差の補正を説明する図であって、球面収差補正レンズを光軸方 向に移動可能な光学系の一例を示す図である。 [20] FIG. 20 is a diagram illustrating a conventional correction of spherical aberration, and is a diagram illustrating an example of an optical system capable of moving a spherical aberration correction lens in an optical axis direction.
[図 21]図 20に示す光学系により、入射瞳位置での光量が変化する状態を示した図 である。  FIG. 21 is a diagram showing a state in which the amount of light at the entrance pupil position changes by the optical system shown in FIG. 20.
符号の説明 Explanation of symbols
A ウェハ (媒質）  A Wafer (medium)
L レーザ光  L laser light
1 レーザ集光光学系  1 Laser focusing optics
2, 103 集光光学系  2, 103 focusing optics
3 レーザ発散点  3 Laser divergence point
4 レーザ発散点移動手段  4 Laser divergence point moving means
10 観察光学系  10 Observation optical system
101 レーザ加工装置  101 Laser processing equipment
104 第 1のレンズ（第 1レンズ群)  104 1st lens (1st lens group)
105 第 2のレンズ（第 2レンズ群)  105 Second lens (second lens group)
106 移動手段  106 means of transportation
107 観察光学系 120 第 2レンズ群 107 Observation optical system 120 Second lens group
125 第 1レンズ群  125 1st lens group
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0034] 以下、本発明に係るレーザ集光光学系及びレーザ加工装置の第 1実施形態を、図 1及び図 2を参照して説明する。  Hereinafter, a first embodiment of a laser focusing optical system and a laser processing apparatus according to the present invention will be described with reference to FIG. 1 and FIG.
本実施形態のレーザ加工装置は、ウェハ (媒質) A中にレーザ光 Lを集光させた状 態で水平方向に走査しながらレーザ加工を行い、ウェハ Aを任意の大きさに切断す ることができる装置であり、図 1に示すようにレーザ集光光学系 1を備えている。また、 本実施形態のレーザ加工装置は、ウェハ Aを水平方向及び鉛直方向に移動可能な 図示しな!、ステージを備えて！/、る。  The laser processing apparatus of the present embodiment performs laser processing while scanning in the horizontal direction in a state where the laser light L is focused on the wafer (medium) A, and cuts the wafer A into an arbitrary size. The apparatus includes a laser condensing optical system 1 as shown in FIG. In addition, the laser processing apparatus of the present embodiment has a stage that can move the wafer A in the horizontal direction and the vertical direction! /
[0035] 上記レーザ集光光学系 1は、レーザ光 Lを平行光束状態で出射するレーザ光源 ( 図示せず）と、このレーザ光源とウェハ Aとの間に配されてレーザ光 Lをウェハ A中に 集光させる対物レンズ等を含む集光光学系 2と、レーザ光 Lのレーザ発散点 3の位置 を、レーザ光 Lを集光させた 、屈折率及びウェハ Aの表面から集光させた 、位置ま での距離に応じて、レーザ光 Lの光軸上に沿って移動可能なレーザ発散点移動手 段 4とを備えている。  The laser condensing optical system 1 includes a laser light source (not shown) that emits the laser light L in a parallel light beam state, and the laser light L The position of the laser divergence point 3 of the laser beam L and the condensing optical system 2 including the objective lens etc. for condensing the laser beam L were condensed from the surface of the wafer A with the refractive index. And a laser divergence point moving means 4 that can move along the optical axis of the laser beam L according to the distance to the position.
なお、本実施形態において、上記レーザ発散点 3は、レーザ光源から出射された平 行光束状態のレーザ光 Lを、所定の光学系により発散光状態 (非平行光束状態）に 変えられた位置を示している。但し、レーザ光源が、レーザ光源を非平行光束状態で 出射可能に設定されている場合には、レーザ光源力も出射される位置がレーザ発散 点 3である。  In the present embodiment, the laser divergence point 3 is a position where the laser beam L emitted from the laser light source in a parallel light flux state is changed to a divergent light state (non-parallel light flux state) by a predetermined optical system. Is shown. However, when the laser light source is set to be able to emit the laser light source in a non-parallel light beam state, the position where the laser light source force is also emitted is the laser divergence point 3.
[0036] 上記レーザ発散点移動手段 4は、図示しない制御部に接続されており、この制御部 力もの信号を受けてレーザ発散点 3を移動するようになっている。また、制御部は、所 定の情報を入力可能な入力部と、この入力部により入力された各入力情報 (入力デ ータ）に基づいてレーザ発散点 3の移動量を計算する計算部とを備えており、計算結 果に応じてレーザ発散点移動手段 4に信号を送って移動させるようになって 、る。 また、制御部は、レーザ発散点移動手段 4の制御に加え、レーザ発散点 3の移動終 了後にレーザ光 Lを出射させるようにレーザ光源の制御も同時に行うようになってい る。 The laser divergence point moving means 4 is connected to a control unit (not shown), and moves the laser divergence point 3 in response to a signal from the control unit. The control unit includes an input unit capable of inputting predetermined information, and a calculation unit that calculates a movement amount of the laser divergence point 3 based on each input information (input data) input by the input unit. A signal is sent to the laser divergence point moving means 4 in accordance with the calculation result, and the laser divergence point moving means 4 is moved. In addition to the control of the laser divergence point moving means 4, the control unit simultaneously controls the laser light source so as to emit the laser light L after the movement of the laser divergence point 3 is completed. The
[0037] このように構成されたレーザ集光光学系 1により、表面力 深さの異なる位置でゥェ ハ A中にレーザ光 Lを集光させると共に、ウェハ Aの走査を行ってこのウェハ Aの切 断を行う場合について説明する。なお、本実施形態においては、深さの異なる位置と して、例えば、表面から 50 m、 75 m、 100 μ mの位置にレーザ光を集光させる場 合を説明する。  With the laser condensing optical system 1 configured as described above, the laser beam L is condensed in the wafer A at positions having different surface forces and the depth of the wafer A is scanned, and the wafer A is scanned. The case where the cutting is performed will be described. In the present embodiment, a case will be described in which laser beams are condensed at positions different in depth, for example, at positions 50 m, 75 m, and 100 μm from the surface.
まず、ウェハ Aの表面から 50 /z mの位置にレーザ光 Lを集光させる場合には、図 2 に示すように、制御部の入力部にウェハ Aの屈折率、ウェハ Aの表面力 集光させた い位置までの距離、即ち、 50 μ m及び集光光学系 2の開口数 NA (Numerical Aperture)の入力を行う（ステップ Sl)。計算部は、この入力データに基づいてレーザ 発散点 3の移動量、即ち、レーザ発散点 3及び集光光学系 2間の距離の計算と、集 光光学系 2及びウェハ Aの表面間の距離、即ち、 WD値の計算とを行う（ステップ S2) 。計算終了後、制御部は、計算結果に基づいてレーザ発散点移動手段 4をレーザ光 Lの光軸方向に移動させるよう制御して、図 1の（a)に示すように、レーザ発散点 3の 位置を所定の位置に移動させると共に、集光光学系 2とウェハ Aとの間の距離 WDを 計算値になるように図示しない移動手段により WDを変化させる (ステップ S3)。  First, when the laser beam L is focused at a position 50 / zm from the surface of the wafer A, as shown in Fig. 2, the refractive index of the wafer A and the surface force of the wafer A are collected at the input of the controller. Input the distance to the position to be made, that is, 50 μm and the numerical aperture NA (Numerical Aperture) of the condenser optical system 2 (Step Sl). The calculation unit calculates the amount of movement of the laser divergence point 3 based on the input data, that is, the distance between the laser divergence point 3 and the converging optical system 2, and the distance between the converging optical system 2 and the surface of the wafer A That is, the WD value is calculated (step S2). After the calculation, the control unit controls the laser divergence point moving means 4 to move in the optical axis direction of the laser beam L based on the calculation result, and as shown in FIG. Is moved to a predetermined position, and WD is changed by a moving means (not shown) so that the distance WD between the condensing optical system 2 and the wafer A becomes a calculated value (step S3).
[0038] レーザ発散点 3の移動及び WDの変化の終了後、制御部は、レーザ光源に信号を 送りレーザ光 Lを出射させる (ステップ S4)。出射されたレーザ光 Lは、レーザ発散点 移動手段 4により所定位置に移動されたレーザ発散点 3の位置にて発散光状態とな つた後、集光光学系 2によりウェハ Aの表面から 50 mの位置に集光される。  After the movement of the laser divergence point 3 and the change of the WD are completed, the control unit sends a signal to the laser light source to emit the laser light L (Step S4). The emitted laser light L enters a divergent light state at the position of the laser divergence point 3 moved to a predetermined position by the laser divergence point moving means 4, and then is condensed by the converging optical system 2 to 50 m from the surface of the wafer A. Is collected at the position.
この際、上述したように、 50 mの深さに応じてレーザ発散点 3の位置を調整してい るので、球面収差の発生量を極力抑えることができ、レーザ光 Lを 50 mの位置に効 率良く集光させることができる。  At this time, as described above, since the position of the laser divergence point 3 is adjusted in accordance with the depth of 50 m, the amount of spherical aberration can be suppressed as much as possible, and the laser beam L is moved to the position of 50 m. Light can be collected efficiently.
[0039] また、ウェハ Aの表面から 75 μ m又は 100 μ mの位置にレーザ光 Lを集光させる場 合には、上述したと同様に、入力部にウェハ Aの屈折率、ウェハ Aの表面から集光さ せたい位置までの距離（75 m又は 100 m)及び集光光学系 2の NAの入力を行う 。計算部による計算終了後、制御部は、計算結果に基づいてレーザ発散点移動手 段 4をレーザ光 Lの光軸方向に移動させるよう制御して、図 1の（b)及び (c)に示すよ うに、レーザ発散点 3の位置を所定の位置に移動させ、 WDを変化させる。その後、 レーザ光 Lを出射させて、集光光学系 2によりレーザ光 Lをウェハ Aの表面から 75 μ m又は 100 μ mの位置に集光させる。 When the laser beam L is focused at a position 75 μm or 100 μm from the surface of the wafer A, the refractive index of the wafer A and the Enter the distance (75 m or 100 m) from the surface to the position to be focused and the NA of the focusing optics 2. After the calculation by the calculation unit is completed, the control unit controls the laser divergence point moving means 4 to move in the optical axis direction of the laser beam L based on the calculation result, and obtains the results shown in FIGS. 1 (b) and (c). I'll show you As described above, the position of the laser divergence point 3 is moved to a predetermined position to change the WD. Thereafter, the laser beam L is emitted, and the laser beam L is focused by the focusing optical system 2 at a position of 75 μm or 100 μm from the surface of the wafer A.
この際、上述したと同様に、 75 m又は 100 mの深さに応じてレーザ発散点 3の 位置を調整して 、るので、それぞれの位置で球面収差の発生量を極力抑えることが でき、レーザ光 Lを 75 μ m又は 100 μ mの位置に効率良く集光させることができる。  At this time, as described above, the position of the laser divergence point 3 is adjusted according to the depth of 75 m or 100 m, so that the amount of spherical aberration generated at each position can be minimized, The laser beam L can be efficiently focused at a position of 75 μm or 100 μm.
[0040] ここで、レーザ光 Lをウェハ A内に集光させると、エネルギーが 1点 (集光点）〖こ集中 してクラックを生じさせる。特に、深さの異なる各位置（50 m、 75 m、 100 μ m)で 球面収差を極力抑えた状態でレーザ光 Lを集光させることが可能であるので、所望 する位置〖こ正確〖こクラックを生じさせることできる。  Here, when the laser beam L is focused on the wafer A, the energy is concentrated at one point (focus point) and a crack is generated. In particular, since it is possible to focus the laser beam L at each position at different depths (50 m, 75 m, 100 μm) while minimizing spherical aberration, the desired position Cracks can occur.
そして、所定の深さにレーザ光 Lを集光させた状態で、ステージを水平方向に走査 してレーザ加工を行うことで、隣接するクラック同士を連結させてウェハ Aを任意の大 きさ、例えば、チップ状に切断することができる。  Then, while the laser beam L is condensed to a predetermined depth, the stage is scanned in the horizontal direction and laser processing is performed, thereby connecting adjacent cracks to each other to make the wafer A have an arbitrary size. For example, it can be cut into chips.
[0041] 上述したように、本実施形態のレーザ加工装置及びレーザ集光光学系 2によれば、 ウェハ A中のそれぞれ異なる深さ（50 m、 75 m、 100 μ m)にレーザ光 Lを集光さ せる際に、ウェハ Aの屈折率及びウェハ Aの表面力 集光させた 、位置までの距離 に応じて、レーザ発散点移動手段 4によりレーザ発散点 3を光軸上に沿って移動させ るので、球面収差の発生量を極力抑えることができ、それぞれの各深さにおいて最 適な状態で効率良くレーザ光 Lを集光させることができる。また、各深さで走査を行う ことで、より正確なレーザ力卩ェを行うことができ、高精度の切断を行うことができる。 特に、レーザ発散点 3を移動させるだけの構成であるので、従来のように手間をか けることなく容易に球面収差補正を行うことができる。また、従来の補正環対物レンズ 等の特別な光学系を必要としないので、構成のシンプノレイ匕を図ることができると共に 低コストィ匕を図ることができる。更に、レーザ発散点 3を移動させるだけであるので、連 続可変を行い易ぐまた自動化への対応がし易い。  As described above, according to the laser processing apparatus and the laser focusing optical system 2 of the present embodiment, the laser beam L is applied to the wafer A at different depths (50 m, 75 m, and 100 μm). When focusing, the laser divergence point 3 is moved along the optical axis by the laser divergence point moving means 4 according to the distance to the position where the refractive index of the wafer A and the surface force of the wafer A are condensed. Accordingly, the amount of generation of spherical aberration can be suppressed as much as possible, and the laser beam L can be efficiently condensed in an optimal state at each depth. In addition, by performing scanning at each depth, more accurate laser power can be obtained, and high-precision cutting can be performed. In particular, since the laser divergence point 3 is simply moved, spherical aberration correction can be easily performed without any trouble as in the related art. In addition, since a special optical system such as a conventional correction ring objective lens is not required, the configuration can be simplified and the cost can be reduced. Furthermore, since the laser divergence point 3 is merely moved, it is easy to continuously change the size and it is easy to respond to automation.
[0042] なお、上記第 1実施形態においては、入力部にウェハ Aの屈折率、ウェハ Aの表面 から集光させた 、位置までの距離及び集光光学系 2の NAを入力することで、レーザ 発散点 3の位置を計算したが、入力データは上述したものに限らず、例えば、これら 入力データに加え、集光光学系 2の予め測定された波面データをさらに入力して、レ 一ザ発散点 3の位置を計算しても構わな 、。 In the first embodiment, the refractive index of the wafer A, the distance from the surface of the wafer A, the distance to the position, and the NA of the focusing optical system 2 are input to the input unit. Although the position of the laser divergence point 3 was calculated, the input data is not limited to the above, and for example, The position of the laser divergence point 3 may be calculated by inputting, in addition to the input data, the previously measured wavefront data of the condensing optical system 2.
即ち、図 3に示すように、入力部への各種データ入力（上述したステップ S1)の際、 ウェハ Aの屈折率、ウェハ Aの表面から集光させたい位置までの距離、集光光学系 2 の NA及び集光光学系 2の波面データを入力する。  That is, as shown in FIG. 3, when inputting various data to the input unit (step S1 described above), the refractive index of the wafer A, the distance from the surface of the wafer A to the position where the light is to be condensed, the condensing optical system 2 Input the NA and the wavefront data of the focusing optics 2.
こうすることで、より高精度に球面収差補正を行うことができ、レーザ光 Lの集光性能 をより向上させることができる。  By doing so, spherical aberration correction can be performed with higher accuracy, and the light-gathering performance of the laser light L can be further improved.
なお、集光光学系 2の波面データとしては、例えば、集光光学系 2を構成している 一部である対物レンズの波面データでも構わないし、集光光学系 2全体の波面デー タを利用しても構わない。  The wavefront data of the condensing optical system 2 may be, for example, the wavefront data of the objective lens which is a part of the condensing optical system 2, or the wavefront data of the entire condensing optical system 2 may be used. It does not matter.
[0043] 次に、本発明の集光光学系の第 2実施形態を、図 4及び図 5を参照して説明する。 Next, a second embodiment of the condensing optical system of the present invention will be described with reference to FIGS.
なお、この第 2実施形態においては、第 1実施形態における構成要素と同一の部分 については、同一の符号を付し、その説明を省略する。  In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
第 2実施形態と第 1実施形態との異なる点は、第 1実施形態では、走査を行う際に、 単にステージを移動させたが、第 2実施形態では、集光光学系 2とウェハ Aの表面と の距離を一定に維持した状態で走査を行う点である。  The difference between the second embodiment and the first embodiment is that in the first embodiment, the stage is simply moved when scanning is performed, but in the second embodiment, the focusing optical system 2 and the wafer A are moved. The point is that scanning is performed with the distance to the surface kept constant.
[0044] 即ち、本実施形態の集光光学系 2は、図 4に示すように、集光光学系 2に連携して 設けられ、集光光学系 2の下面力 ウェハ Aの表面までの距離を所定の距離に維持 する観察光学系 10を備えている。また、この観察光学系 10は、オートフォーカス機構 を有している。 That is, as shown in FIG. 4, the condensing optical system 2 of the present embodiment is provided in cooperation with the condensing optical system 2, and the lower surface force of the condensing optical system 2 is the distance to the surface of the wafer A. An observation optical system 10 for maintaining the distance at a predetermined distance is provided. The observation optical system 10 has an autofocus mechanism.
上記観察光学系 10は、直線偏光の半導体レーザ光 L'を照射する光源 11、この光 源 11力 照射された半導体レーザ光 L，を平行光にする第 1のレンズ 12、この第 1の レンズ 12に隣接配置された偏光ビームスプリッタ 13、この偏光ビームスプリッタ 13を 透過した半導体レーザ光 L，を収束させる第 2のレンズ 14、この第 2のレンズ 14により 収束された半導体レーザ光 L，を再度平行光にする第 3のレンズ 15、この第 3のレン ズ 15を透過した直線偏光である半導体レーザ光 L'を円偏光にする 1Z4波長板 16 、この 1Z4波長板 16を透過した半導体レーザ光 L'を、光軸の向きを 90度変えるよう に反射させて集光光学系 2に入射させるダイクロイツクミラー 17、再度 1 Z4波長板 16 を透過し上記偏光ビームスプリッタ 13で反射された集光光学系 2からの戻り光を、シ リンドリカルレンズ 18に入射させる第 4のレンズ 19及びシリンドリカルレンズ 18の後側 に配されたフォトダイオード 20を備えて ヽる。 The observation optical system 10 includes a light source 11 for irradiating linearly polarized semiconductor laser light L ′, a light source 11, a first lens 12 for making the irradiated semiconductor laser light L parallel, and a first lens 12. 12, a second lens 14 for converging the semiconductor laser light L transmitted through the polarization beam splitter 13, and a semiconductor laser light L converged by the second lens 14 again. A third lens 15 to make parallel light, a semiconductor laser light L ′ which is linearly polarized light transmitted through the third lens 15 and a circularly polarized light L ′ is a 1Z4 wavelength plate 16, and a semiconductor laser light which is transmitted to this 1Z4 wavelength plate 16 A dichroic mirror 17 that reflects L ′ so that the direction of the optical axis is changed by 90 degrees and enters the condensing optical system 2, and again a 1 Z4 wave plate 16 A fourth lens 19 that allows the return light from the condensing optical system 2 that has passed through and reflected by the polarization beam splitter 13 to be incident on the cylindrical lens 18 and a photodiode 20 disposed on the rear side of the cylindrical lens 18 Equipped with
なお、ダイクロイツクミラー 17は、半導体レーザ光 L'を反射すると共に、それ以外の 波長の光、例えば、レーザ光源で出射されたレーザ光 Lを透過するよう設定されてい る。  The dichroic mirror 17 is set so as to reflect the semiconductor laser light L ′ and transmit light of other wavelengths, for example, the laser light L emitted from the laser light source.
[0045] 上記偏光ビームスプリッタ 13は、直線偏光のうち、例えば、入射面に平行な振動成 分である P成分の直線偏光の光を透過させると共に、入射面に垂直な振動成分であ る S成分の光を反射させる機能を有している。また、制御部は、上記フォトダイオード 20により受光されたフォーカシングエラー信号等の検出信号に基づいてステージを フィードバック制御して、ステージを鉛直方向（光軸方向）に移動させるようになつてい る。即ち、オートフォーカスするようになっている。これにより、半導体レーザ光 L'は、 常にウェハ Aの表面に焦点が合うように調整される。  The polarization beam splitter 13 transmits, for example, a linearly polarized light of P component, which is a vibration component parallel to the incident surface, of the linearly polarized light, and a vibration component S perpendicular to the incident surface. It has the function of reflecting component light. Further, the control unit performs feedback control of the stage based on a detection signal such as a focusing error signal received by the photodiode 20, and moves the stage in the vertical direction (optical axis direction). That is, automatic focusing is performed. Thereby, the semiconductor laser light L ′ is adjusted so that the surface of the wafer A is always focused.
[0046] このように構成された集光光学系 2においては、ウェハ Aの走査を行う際、光源 11 力も直線偏光の半導体レーザ光 L'の照射を行う。照射された半導体レーザ光 L'は、 第 1のレンズ 12により平行光となった後、偏光ビームスプリッタ 13に入射する。そして 、入射面に平行な振動成分である P成分の直線偏光の光となった後、第 2のレンズ 1 4により収束された後、発散状態となる。そして、発散された光は、第 3のレンズ 15に より再度平行光となって 1Z4波長板 16に入射する。なお、この際、平行光は、集光 光学系 2に応じた光束の幅となっている。 1Z4波長板 16を透過して円偏光となった 半導体レーザ光 L'は、ダイクロイツクミラー 17で反射されて集光光学系 2に入射する 。集光光学系 2に入射した光は、ウェハ Aの表面に照明される。  In the condensing optical system 2 configured as described above, when scanning the wafer A, the light source 11 irradiates the semiconductor laser light L ′ that is also linearly polarized. The irradiated semiconductor laser light L ′ is converted into parallel light by the first lens 12 and then enters the polarization beam splitter 13. Then, the light becomes linearly polarized light having a P component, which is a vibration component parallel to the incident surface, and is then converged by the second lens 14 to be in a divergent state. Then, the diverged light becomes parallel light again by the third lens 15 and enters the 1Z4 wavelength plate 16. At this time, the parallel light has the width of the light beam corresponding to the condensing optical system 2. The semiconductor laser light L ′ that has passed through the 1Z4 wavelength plate 16 and has become circularly polarized is reflected by the dichroic mirror 17 and is incident on the condenser optical system 2. The light incident on the condensing optical system 2 illuminates the surface of the wafer A.
[0047] 次 、で、ウェハ Aの表面で反射した光は、集光光学系 2で集光された後、ダイクロイ ックミラー 17で反射されて 1 Z4波長板 16に入射し、入射面に垂直な振動成分であ る S成分偏光となる。この光は、第 3のレンズ 15及び第 2のレンズ 14を透過した後、偏 光ビームスプリッタ 13に入射して第 4のレンズ 19に向けて反射される。そして、第 4の レンズ 19により収束された後、シリンドリカルレンズ 18を透過してフォトダイオード 20 上に結像される。この結像されたフォーカシングエラー信号等の検出信号は、制御部 に送られる (ステップ S5)。この制御部は、送られてきた検出信号に基づいて計算を 行い (ステップ S6)、半導体レーザ光 L'の焦点がウェハ Aの表面に合うようにステー ジを鉛直方向（光軸方向）に移動させる (ステップ S 7)。即ち、自動的にオートフォー カスを行って、ウェハ Aの表面を常に撮像するように制御を行う。 Next, the light reflected on the surface of the wafer A is condensed by the condensing optical system 2, is reflected by the dichroic mirror 17 and is incident on the 1 Z4 wave plate 16, and is perpendicular to the incident surface. S-polarized light, which is the vibration component. This light passes through the third lens 15 and the second lens 14, then enters the polarization beam splitter 13 and is reflected toward the fourth lens 19. After being converged by the fourth lens 19, the light passes through the cylindrical lens 18 and is imaged on the photodiode 20. The detection signal such as the focused focusing error signal is transmitted to the control unit. (Step S5). The control unit calculates based on the sent detection signal (step S6), and moves the stage vertically (optical axis direction) so that the focus of the semiconductor laser light L 'is on the surface of the wafer A. (Step S7). That is, control is performed such that the automatic focusing is performed and the surface of the wafer A is always imaged.
[0048] これにより、集光光学系 2とウェハ Aの表面との距離を、常に一定の距離に維持しな 力 走査を行うことができる。従って、仮にステージが若干湾曲していたり、ステージ の移動に多少の誤差等が生じていたとしても、正確に所望の深さにレーザ光 Lを集 光させることができる。よって、ウェハ Aの表面力 の集光位置をより正確に制御しな 力 走査を行うことができ、より高精度のレーザ力卩ェが行える。  As a result, it is possible to perform force scanning without always keeping the distance between the condensing optical system 2 and the surface of the wafer A at a constant distance. Therefore, even if the stage is slightly curved or a slight error occurs in the movement of the stage, the laser beam L can be accurately collected to a desired depth. Therefore, it is possible to perform the power scanning without more accurately controlling the condensing position of the surface force of the wafer A, and it is possible to perform the laser power control with higher precision.
[0049] なお、上述した走査を行う際に、レーザ光 Lを集光させる位置を変更する場合、ォ 一トフォーカスのオフセット量計算 (ステップ S8)を事前に行った後、走査を行う。例え ば、 100 mの深さに集光させた状態で走査を行った後に、 50 mの深さに集光さ せて走査を行う場合には、レーザ発散点の移動と共に WD値を変更して最適な状態 、即ち、最適値に設定する必要がある。この WD値の変更に伴って、オートフォーカス を所定量だけオフセットする必要が生じる。つまり、オートフォーカスのオフセット量を 計算することで、 WD値の補正が行える。そして、オフセットを行った後に、上述したと 同様に異なる深さでの走査が行える。  When the position where laser light L is condensed is changed during the above-described scanning, the scanning is performed after the calculation of the amount of offset of the autofocus (step S8) is performed in advance. For example, when scanning at a depth of 100 m and then scanning at a depth of 50 m, the WD value must be changed along with the movement of the laser divergence point. It is necessary to set the optimum state, that is, the optimum value. With the change of the WD value, it is necessary to offset the auto focus by a predetermined amount. In other words, the WD value can be corrected by calculating the autofocus offset amount. Then, after performing the offset, scanning at a different depth can be performed as described above.
[0050] 次に、本発明の集光光学系の第 3実施形態を、図 6及び図 7を参照して説明する。  Next, a third embodiment of the light collecting optical system of the present invention will be described with reference to FIGS. 6 and 7.
なお、この第 3実施形態においては、第 1実施形態における構成要素と同一の部分 については、同一の符号を付し、その説明を省略する。  In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
第 3実施形態と第 1実施形態との異なる点は、第 1実施形態では、集光光学系 2とゥ エノ、 Aの表面との光軸方向の相対的な距離、即ち、 WDが一定でな力つたのに対し 、第 3実施形態では、 WDが一定とされている点である。  The difference between the third embodiment and the first embodiment is that in the first embodiment, the relative distance in the optical axis direction between the light-collecting optical system 2 and the surface of the optics A, that is, the WD is constant. On the other hand, in the third embodiment, the WD is fixed.
即ち、ステージ及び集光光学系 2の光軸方向における位置を、予め事前に設定し た後、両者の位置を常に同じ位置に維持するように設定を行うようになっている。つま り、図 6に示すように、入力部への各種データ入力（上述したステップ S1)の際、 WD 値を除いたデータ、即ち、ウェハ Aの屈折率、ウェハ Aの表面から集光させたい位置 までの距離及び集光光学系 2の NAのデータの入力を行う。 こうすることで、図 7に示すように、 WDを一定にした状態で、レーザ発散点移動手 段 4によりレーザ発散点 3のみを光軸方向に沿って移動させるので、より簡単な構成 で球面収差の補正を行うことができる。 That is, after the positions of the stage and the condensing optical system 2 in the optical axis direction are set in advance, the settings are made so that the positions of the two are always maintained at the same position. In other words, as shown in FIG. 6, when inputting various data to the input unit (step S1 described above), it is desirable to collect data excluding the WD value, that is, the refractive index of the wafer A and the light from the surface of the wafer A. Enter the distance to the position and NA data of the focusing optics 2. By doing so, as shown in Fig. 7, the laser divergence point moving means 4 moves only the laser divergence point 3 along the optical axis direction while keeping the WD constant, so that the spherical surface can be simplified with a simpler configuration. Aberration correction can be performed.
[0051] 次に、本発明の集光光学系の第 4実施形態を、図 8及び図 9を参照して説明する。 Next, a light collecting optical system according to a fourth embodiment of the present invention will be described with reference to FIGS. 8 and 9.
なお、この第 4実施形態においては、第 2実施形態における構成要素と同一の部分 については、同一の符号を付し、その説明を省略する。  In the fourth embodiment, the same components as those in the second embodiment are denoted by the same reference numerals, and description thereof will be omitted.
第 4実施形態と第 2実施形態との異なる点は、第 2実施形態では、集光光学系 2とゥ エノ、 Aの表面との光軸方向の相対的な距離、即ち、 WDが一定でな力つたのに対し 、第 4実施形態では、 WDが一定とされている点である。  The difference between the fourth embodiment and the second embodiment is that, in the second embodiment, the relative distance in the optical axis direction between the condensing optical system 2 and the surface of each of the optics and A, that is, the WD is constant. On the other hand, in the fourth embodiment, the WD is fixed.
即ち、本実施形態の集光光学系 2は、図 8に示すように、上記第 3実施形態と同様 に WDが一定とされている状態でオートフォーカスを行いながら走査を行うことができ る。従って、図 9に示すように、オートフォーカスのオフセット量を初期に設定した後に 、再度オフセット量を計算する必要がないので、オフセットにかける時間を短縮でき、 スループットの向上を図ることができる。  That is, as shown in FIG. 8, the condensing optical system 2 of the present embodiment can perform scanning while performing auto-focusing with the WD kept constant, as in the third embodiment. Therefore, as shown in FIG. 9, there is no need to calculate the offset amount again after initially setting the offset amount of the autofocus, so that the time required for the offset can be reduced and the throughput can be improved.
また、オフセットを行うことにより生じるオートフォーカスの精度の劣化を小さくするこ とがでさる。  In addition, it is possible to reduce the deterioration of the autofocus accuracy caused by performing the offset.
[0052] なお、本発明の技術範囲は、上記実施形態に限定されるものではなぐ本発明の 趣旨を逸脱しない範囲において、種々の変更をカ卩えることが可能である。  The technical scope of the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention.
例えば、上記各実施形態において、ウェハ内にレーザ光を集光させたが、ウェハに 限らず媒質中に集光させれば構わない。また、集光させたい距離として、ウェハの表 面力ら 50 m、 75 m、 100 μ mの距離とした力 これらの距離に限らず、任意に設 定して構わない。また、ステージを移動させて、集光光学系とウェハの表面との光軸 方向の相対的な距離を変化させたが、これに限らず、例えば、集光光学系をピエゾ 素子等を利用して移動させることで、相対的な距離を変化させても構わない。  For example, in each of the above embodiments, the laser light is focused in the wafer, but the laser light may be focused not only in the wafer but also in the medium. Also, the distance to be focused is set to a distance of 50 m, 75 m, or 100 μm from the surface force of the wafer. The force is not limited to these distances, and may be set arbitrarily. In addition, the relative distance in the optical axis direction between the condensing optical system and the surface of the wafer was changed by moving the stage. However, the present invention is not limited to this. For example, the condensing optical system may use a piezo element or the like. The relative distance may be changed by moving the object.
また、制御部によりレーザ発散点移動手段を自動的に制御するように構成したが、 制御部による計算結果に基づいて、手段によりレーザ発散点移動手段を作動させて レーザ発散点の位置を移動させても構わな 、。  In addition, the laser divergence point moving means is automatically controlled by the control unit.However, based on the calculation result by the control unit, the laser divergence point moving means is operated by the means to move the position of the laser divergence point. It doesn't matter.
[0053] また、上記第 3実施形態で説明した観察光学系は一例であり、集光光学系の下面 力 ウェハの表面までの距離を所定距離に維持可能であれば、レンズ等の各光学系 を組み合わせて構成して構わな 、。 The observation optical system described in the third embodiment is an example, and the lower surface of the converging optical system is As long as the distance to the surface of the wafer can be maintained at a predetermined distance, each optical system such as a lens may be combined.
[0054] 以下、本発明に係るレーザ加工装置の第 5実施形態を、図 10及び図 11を参照し て説明する。  Hereinafter, a fifth embodiment of the laser processing apparatus according to the present invention will be described with reference to FIG. 10 and FIG.
本実施形態のレーザ加工装置 101は、図 10に示すように、レーザ光 Lを射出する 図示しないレーザ光源と、このレーザ光源力 射出されたレーザ光 Lの光束を平行光 束にする図示しないレンズ等の平行光束手段と、平行光束状態のレーザ光 Lを媒質 中に集光させる対物レンズ 102を有する集光光学系 103と、平行光束手段と対物レ ンズ 102との間の平行光束中に、平行光束の光軸方向に沿って移動可能に配され た第 1のレンズ（第 1レンズ群） 104と、この第 1のレンズ 104と対物レンズ 102との間 の平行光束中に固定された状態で配された第 2のレンズ (第 2レンズ群） 105と、レー ザ光 Lを集光させた 、ウェハ（媒質) Aの屈折率及びウェハ Aの表面力も集光させた い位置までの距離に応じて第 1のレンズ 104を移動させる移動手段 106と、集光光学 系 103に連係して設けられ、対物レンズ 102の下面からウェハ Aの表面までの距離 を所定の距離に維持する観察光学系 107とを備えて 、る。  As shown in FIG. 10, a laser processing apparatus 101 of the present embodiment includes a laser light source (not shown) that emits a laser beam L, and a lens (not shown) that converts the laser beam L emitted from the laser light source into a parallel light beam. And a converging optical system 103 having an objective lens 102 for converging the laser beam L in a parallel light beam state into a medium; and a parallel light beam between the parallel light beam means and the objective lens 102. A first lens (first lens group) 104 movably arranged along the optical axis direction of the parallel light beam, and a state fixed in the parallel light beam between the first lens 104 and the objective lens 102 The distance between the second lens (second lens group) 105 arranged at the point and the position where the laser beam L is condensed and the refractive index of the wafer (medium) A and the surface force of the wafer A are also condensed Moving means 106 for moving the first lens 104 in accordance with And an observation optical system 107 provided in cooperation with the main body to maintain a predetermined distance from the lower surface of the objective lens 102 to the surface of the wafer A.
なお、ウェハ Aは、 XY方向に移動可能な図示しないステージ上に載置されている  The wafer A is mounted on a stage (not shown) that can move in the X and Y directions.
[0055] 上記第 1のレンズ 104は、両凹レンズであり、図示しないレンズ枠に固定されている 。上記移動手段 106は、レンズ枠に接続されており、レンズ枠を介して第 1のレンズ 1 04を移動するようになっている。また、移動手段 106は、図示しない制御部に接続さ れており、この制御部からの信号を受けて作動するようになっている。 [0055] The first lens 104 is a biconcave lens, and is fixed to a lens frame (not shown). The moving means 106 is connected to the lens frame, and moves the first lens 104 via the lens frame. The moving means 106 is connected to a control unit (not shown), and operates by receiving a signal from the control unit.
この制御部は、所定の情報を入力可能な入力部と、この入力部により入力された各 入力情報 (入力データ）に基づいて第 1のレンズ 104の移動量を計算する計算部とを 備えており、計算結果に応じて移動手段 106を所定量移動させるようになつている。 また、制御部は、移動手段 106の制御部に加え、第 1のレンズ 104の移動終了後に 光束を射出させるようにレーザ光源の制御も行うようになって 、る。  The control unit includes an input unit capable of inputting predetermined information, and a calculation unit that calculates a movement amount of the first lens 104 based on each input information (input data) input by the input unit. The moving means 106 is moved by a predetermined amount according to the calculation result. The control unit also controls the laser light source so as to emit a light beam after the movement of the first lens 104 is completed, in addition to the control unit of the moving unit 106.
[0056] 上記第 2のレンズ 105は、凸レンズであり、平面側を第 1のレンズ 104側に向けて、 即ち、凸面側を対物レンズ 102側に向けて、後側焦点位置が対物レンズ 102の入射 瞳位置の少なくとも近傍になる位置に配されている。 The second lens 105 is a convex lens, and the flat side faces the first lens 104 side, that is, the convex side faces the objective lens 102 side, and the rear focal position of the second lens 105 is incident It is arranged at a position at least near the pupil position.
[0057] 上記観察光学系 107は、直線偏光の半導体レーザ光 L'を照射する光源 110、この 光源 110から照射された半導体レーザ光 L'を平行光にする第 1のレンズ 111、この 第 1のレンズ 111に隣接配置された偏光ビームスプリッタ 112、この偏光ビームスプリ ッタ 112を透過した半導体レーザ光 L'を収束及び発散させる第 2のレンズ 113、この 第 2のレンズ 113により発散された半導体レーザ光 L，を平行光にする第 3のレンズ 1 14、この第 3のレンズ 114を透過した半導体レーザ光 L'の偏光を円偏光にする 1Z4 波長板 115、この 1Z4波長板 115を透過した半導体レーザ光 L'を、光軸の向きを 9 0度変えるように反射させて対物レンズ 102に入射させるダイクロイツクミラー 116、対 物レンズ 102からの戻り光のうち上記偏光ビームスプリッタ 112で反射された半導体 レーザ光 L，をシリンドリカルレンズ 117に入射させる第 4のレンズ 118及びシリンドリカ ルレンズ 117の後側に配されたフォトダイオード 119を備えて!/、る。  The observation optical system 107 includes a light source 110 that irradiates a linearly polarized semiconductor laser light L ′, a first lens 111 that converts the semiconductor laser light L ′ emitted from the light source 110 into parallel light, A polarizing beam splitter 112 disposed adjacent to the first lens 111, a second lens 113 for converging and diverging the semiconductor laser light L ′ transmitted through the polarizing beam splitter 112, and a semiconductor diverged by the second lens 113. A third lens 114 that converts the laser light L into parallel light, a 1Z4 wavelength plate 115 that converts the polarization of the semiconductor laser light L ′ transmitted through the third lens 114 into circularly polarized light, and a light that passes through the 1Z4 wavelength plate 115 The dichroic mirror 116, which reflects the semiconductor laser light L 'so as to change the direction of the optical axis by 90 degrees and makes it incident on the objective lens 102, is reflected by the polarization beam splitter 112 out of the return light from the objective lens 102. Semiconductor laser A fourth lens 118 for allowing the light L to enter the cylindrical lens 117 and a photodiode 119 disposed on the rear side of the cylindrical lens 117 are provided.
なお、ダイクロイツクミラー 116は、半導体レーザ光 L'を反射すると共にそれ以外の 波長の光、例えば、レーザ光源で射出されたレーザ光 Lを透過するよう設定されてい る。  The dichroic mirror 116 is set to reflect the semiconductor laser light L ′ and transmit light of other wavelengths, for example, the laser light L emitted from a laser light source.
[0058] 上記偏光ビームスプリッタ 112は、直線偏光のうち、例えば、入射面に平行な振動 成分である P成分の直線偏光の光を透過させると共に、入射面に垂直な振動成分で ある S成分の光を反射させる機能を有している。また、制御部は、上記フォトダイォー ド 119により受光されたフォーカシングエラー信号等の検出信号に基づいてステージ をフィードバック制御して、ステージを鉛直方向（光軸方向）に移動させるようになって いる。即ち、オートフォーカスするようになっている。これにより、半導体レーザ光 L，は 、常にウェハ Aの表面に焦点が合うように調整される。  [0058] The polarization beam splitter 112 transmits, for example, linearly polarized light of a P component, which is a vibration component parallel to the incident surface, of the linearly polarized light, and S component, which is a vibration component perpendicular to the incident surface. It has the function of reflecting light. The control unit performs feedback control of the stage based on a detection signal such as a focusing error signal received by the photodiode 119 to move the stage in the vertical direction (optical axis direction). That is, automatic focusing is performed. Thereby, the semiconductor laser light L is adjusted so that the surface of the wafer A is always focused.
[0059] このように構成されたレーザカ卩ェ装置 101により、ウェハ Aの表面力も深さの異なる 位置にレーザ光 Lを集光してレーザ加工を行う場合について説明する。  A case will be described in which laser processing is performed by concentrating laser light L at a position where the surface force of wafer A also has a different depth by laser laser apparatus 101 configured as described above.
まず、図 11に示すように、制御部の入力部にウェハ Aの屈折率、ウェハ Aの表面か ら集光させたい位置までの距離、例えば、 50 ^ m,対物レンズ 102の NA、対物レン ズ 102とウェハ Aの表面との距離、即ち、 WD値及び対物レンズ 102の予め測定され た波面データを入力する (ステップ S1A)。計算部は、これら入力されたデータに基 づいて第 1のレンズ 104の移動量の計算を行う（ステップ S2A)。計算終了後、制御 部は、計算結果に基づ!/、て移動手段 106を光軸方向に移動させるように制御して、 第 1のレンズ 104の位置を所定の位置に移動させる（ステップ S3A)。 First, as shown in FIG. 11, the refractive index of the wafer A, the distance from the surface of the wafer A to the position to be focused, for example, 50 m, the NA of the objective lens 102, the objective lens The distance between the lens 102 and the surface of the wafer A, that is, the WD value and the previously measured wavefront data of the objective lens 102 are input (step S1A). The calculation unit calculates the data based on the input data. Then, the amount of movement of the first lens 104 is calculated (step S2A). After the calculation, the control unit controls the moving means 106 in the optical axis direction based on the calculation result to move the position of the first lens 104 to a predetermined position (step S3A). ).
[0060] 第 1のレンズ 104の移動終了後、制御部は、レーザ光源に信号を送り、レーザ光 L を射出させる (ステップ S4A)。射出されたレーザ光 Lは、平行光束手段により平行光 束に変換されて、第 1のレンズ 104に入射する。そして、レーザ光 Lは、第 1のレンズ 1 04で屈折して発散光状態となり、第 2のレンズ 105に入射する。つまり、第 1のレンズ 104を移動させることで、光軸方向におけるレーザ光 Lの発散点位置を変更している 。発散光となったレーザ光 Lは、第 2のレンズ 105により再度屈折した後、対物レンズ 102に入射してウェハ Aの表面力 所望する深さ（50 m)に集光される。  [0060] After the movement of the first lens 104 is completed, the control unit sends a signal to the laser light source to emit the laser light L (Step S4A). The emitted laser light L is converted into a parallel light beam by the parallel light beam means and enters the first lens 104. Then, the laser light L is refracted by the first lens 104 to be in a divergent light state, and is incident on the second lens 105. That is, the position of the divergence point of the laser light L in the optical axis direction is changed by moving the first lens 104. The divergent laser light L is refracted again by the second lens 105, then enters the objective lens 102, and is condensed to a desired depth (50 m) of the surface force of the wafer A.
この際、上述したように、所望する深さに応じて第 1のレンズ 104の位置を光軸方向 に移動させて発散点位置を調整して 、るので、球面収差の発生量を極力抑えること ができ、レーザ光 Lを所望する位置に効率良く集光させることができる。  At this time, as described above, the position of the first lens 104 is moved in the optical axis direction according to the desired depth to adjust the position of the divergence point, so that the amount of spherical aberration generated is minimized. Thus, the laser beam L can be efficiently focused on a desired position.
[0061] また、上述した集光点とは異なる位置、即ち、異なる深さにレーザ光 Lを集光させる 場合には、上述したと同様にウェハ Aの表面力 の新たな距離を含むデータを入力 部に入力する。制御部は、計算部による計算結果に基づいて、移動手段 106を作動 させて第 1のレンズ 104を光軸方向に沿って新たな位置に移動させる。これにより、レ 一ザ光 Lは、上述した位置とは異なる位置で屈折して発散光状態となり第 2のレンズ 105に入射する。この際、レーザ光 Lは、第 1のレンズ 104に平行光束状態で入射す るので、第 1のレンズ 104力 光軸に沿って移動した場合でも、第 1のレンズ 104に入 射する光線の光軸からの距離（s)が一定であれば、第 1のレンズ 104を通過後の光 線の角度 (q)は変化しな 、（平行である）。それら角度が変化しな 、（平行な）光線は 、第 2のレンズ 105の後側焦面上の 1点に集光する（必ず通る）。第 2のレンズ 105の 後側焦点位置と集光光学系 103の入射瞳位置とがー致するように配置されており、 第 1のレンズ 104に入射した平行光束は、第 1のレンズ 104の位置によらず、集光光 学系 103の入射瞳位置で常に同じ光束径となり、集光光学系 103でけられることなく 集光する。集光光学系 103に入射する光束径は変化することはないので、従来のよ うな集光位置での光量の変化や瞳面内での光量分布の変化を抑えることができる。 [0062] ここで、レーザ光 Lをウェハ A内に集光させると、エネルギーが 1点 (集光点）〖こ集中 してクラックを生じさせる。特に、深さの異なる位置に球面収差を極力抑えた状態でレ 一ザ光 Lを集光させることが可能であるので、所望する位置に正確にクラックを生じさ せることができる。そして、所定の深さにレーザ光 Lを集光させた状態で、ステージを 水平方向に走査してレーザ加工を行うことで、隣接するクラック同士を連結させてゥ ェハ Aを任意の大きさ、例えば、チップ状に切断することができる。 When the laser beam L is condensed at a position different from the above-mentioned converging point, that is, at a different depth, data including a new distance of the surface force of the wafer A is transmitted as described above. Input to the input section. The control unit operates the moving unit 106 based on the calculation result by the calculation unit to move the first lens 104 to a new position along the optical axis direction. As a result, the laser light L is refracted at a position different from the above-mentioned position, enters a divergent light state, and enters the second lens 105. At this time, since the laser beam L is incident on the first lens 104 in a parallel light flux state, even if the laser beam L moves along the optical axis of the first lens 104, the light beam entering the first lens 104 If the distance (s) from the optical axis is constant, the angle (q) of the light beam after passing through the first lens 104 does not change (is parallel). The light rays (parallel) whose angles do not change converge (must pass) at one point on the rear focal plane of the second lens 105. The rear focal position of the second lens 105 and the entrance pupil position of the condensing optical system 103 are arranged so as to be coincident with each other, and the parallel light beam incident on the first lens 104 is Irrespective of the position, the light beam diameter always becomes the same at the entrance pupil position of the condensing optical system 103, and the light is condensed without being shaken by the condensing optical system 103. Since the diameter of the light beam incident on the condensing optical system 103 does not change, it is possible to suppress the change in the light amount at the light condensing position and the change in the light amount distribution in the pupil plane as in the related art. Here, when the laser light L is focused on the wafer A, the energy is concentrated at one point (focus point) and a crack is generated. In particular, since the laser beam L can be condensed at positions having different depths while suppressing spherical aberration as much as possible, a crack can be accurately generated at a desired position. Then, while the laser beam L is condensed to a predetermined depth, the stage is scanned in the horizontal direction to perform laser processing, thereby connecting adjacent cracks to each other to make the wafer A to an arbitrary size. For example, it can be cut into chips.
[0063] 特に、本実施形態においては、観察光学系 107を備えているので走査を行う際に 対物レンズ 102とウェハ Aの表面との距離を一定にした状態で走査を行うことができ る。  In particular, in the present embodiment, since the observation optical system 107 is provided, the scanning can be performed with the distance between the objective lens 102 and the surface of the wafer A kept constant.
即ち、走査を行う際、光源 110から直線偏光の半導体レーザ光 L'を照射する。照 射された半導体レーザ光 L'は、第 1のレンズ 111により平行光となった後、偏光ビー ムスプリッタ 112に入射する。そして、入射面に平行な振動成分である P成分の直線 偏光となった後、第 2のレンズ 113により収束された後、発散状態となる。そして、発 散された光は、第 3のレンズ 114により再度平行光となって 1Z4波長板 115に入射 する。なお、この際、平行光は、対物レンズ 102に応じた光束の幅となっている。 1/ 4波長板 115を透過して円偏光となった半導体レーザ光 L'は、ダイクロイツクミラー 1 16で反射されて対物レンズ 102に入射する。対物レンズ 102に入射した光は、ゥェ ハ Aの表面に照明される。  That is, when scanning, the light source 110 emits linearly polarized semiconductor laser light L ′. The illuminated semiconductor laser light L ′ is converted into parallel light by the first lens 111 and then enters the polarization beam splitter 112. Then, after becoming a linearly polarized light of a P component which is a vibration component parallel to the incident surface, the light is converged by the second lens 113 and then diverged. Then, the diverged light becomes parallel light again by the third lens 114 and enters the 1Z4 wavelength plate 115. Note that, at this time, the parallel light has a light beam width corresponding to the objective lens 102. The semiconductor laser light L ′ that has passed through the quarter-wave plate 115 and has become circularly polarized is reflected by the dichroic mirror 116 and enters the objective lens 102. The light that has entered the objective lens 102 illuminates the surface of the wafer A.
[0064] 次 、で、ウェハ Aの表面で反射した光は、対物レンズ 102で集光された後、ダイク口 イツクミラー 116で反射された 1 Z4波長板 115に入射し、入射面に垂直な振動成分 である S成分の偏光となる。この光は、第 3のレンズ 114及び第 2のレンズ 113を透過 した後に、偏光ビームスプリッタ 112に入射して、第 4のレンズ 118に向けて反射され る。そして、第 4のレンズ 118により収束された後、シリンドリカルレンズ 117を透過し てフォトダイオード 119上に結像される。この結像されたフォーカシングエラー信号等 の検出信号は、制御部に送られる (ステップ S 5 A)。制御部は、送られてきた検出信 号に基づ 、て計算を行 、 (ステップ S6A)、半導体レーザ光 L'の焦点がウェハ Aの 表面に合うようにステージを鉛直方向（光軸方向）に移動させる (ステップ S7A)。即 ち、自動的にオートフォーカスを行って、集光光学系 103とウェハ Aの表面との距離 が常に一定になる様に制御する。 Next, the light reflected on the surface of the wafer A is condensed by the objective lens 102, then enters the 1 Z4 wave plate 115 reflected by the dike opening mirror 116, and vibrates perpendicularly to the incident surface. The polarization of the S component, which is the component. This light passes through the third lens 114 and the second lens 113, then enters the polarization beam splitter 112, and is reflected toward the fourth lens 118. Then, after being converged by the fourth lens 118, the light passes through the cylindrical lens 117 and forms an image on the photodiode 119. The formed detection signal such as a focusing error signal is sent to the control unit (step S5A). The control unit performs a calculation based on the sent detection signal (step S6A), and moves the stage in the vertical direction (optical axis direction) so that the focus of the semiconductor laser light L 'is on the surface of the wafer A. (Step S7A). Immediately That is, automatic focusing is performed, and control is performed so that the distance between the condensing optical system 103 and the surface of the wafer A is always constant.
[0065] これにより、対物レンズ 102とウェハ Aの表面との距離を常に一定の距離に維持し ながら走査を行うことができる。従って、仮にステージが若干湾曲していたり、ステー ジの移動に多少の誤差等が生じていたりしても、正確にレーザ光 Lを所望の深さに集 光させることができる。よって、ウェハ Aの表面から集光位置をより正確に制御しなが ら走査を行うことができ、より高精度にレーザ加工が行える。  [0065] Thereby, scanning can be performed while always keeping the distance between the objective lens 102 and the surface of the wafer A at a constant distance. Therefore, even if the stage is slightly curved or the stage moves with some error, the laser beam L can be accurately focused to a desired depth. Therefore, scanning can be performed while controlling the focusing position more accurately from the surface of the wafer A, and laser processing can be performed with higher precision.
[0066] なお、上述した走査を行う際に、レーザ光 Lを集光させる位置を変更させる場合、ォ 一トフォーカスのオフセット量計算 (ステップ S8A)を事前に行った後、走査を行う。例 えば、表面から 100 mの深さにレーザ光 Lを集光させた状態で走査を行った後に、 50 μ mの深さに集光させて走査を行う場合には、 WD値を最適値に設定する必要が ある。この WD値の変更に伴って、オートフォーカスを所定量だけオフセットする必要 力 S生じる。つまり、オートフォーカスのオフセット量を計算することで、 WD値の補正が 行える。この補正を行った後に、異なる深さの走査を行う。  When the position at which the laser light L is condensed is changed during the above-described scanning, the scanning is performed after the calculation of the amount of offset of the autofocus (Step S8A) is performed in advance. For example, if scanning is performed with the laser beam L focused at a depth of 100 m from the surface and then focused at a depth of 50 μm, the WD value should be set to the optimum value. Must be set to With the change of the WD value, a necessary force S for offsetting the auto focus by a predetermined amount occurs. In other words, the WD value can be corrected by calculating the autofocus offset amount. After performing this correction, scanning at different depths is performed.
[0067] 次に、本発明のレーザ加工装置の第 6実施形態を、図 12を参照して説明する。な お、この第 6実施形態においては、第 5実施形態における構成要素と同一の部分に ついては、同一の符号を付し、その説明を省略する。  Next, a sixth embodiment of the laser processing apparatus of the present invention will be described with reference to FIG. In the sixth embodiment, the same components as those in the fifth embodiment are denoted by the same reference numerals, and description thereof is omitted.
第 6実施形態と第 5実施形態との異なる点は、第 5実施形態では、対物レンズ 102と ウエノ、 Aの表面との光軸方向の相対的な距離、即ち、 WDが一定でな力つたのに対 し、第 6実施形態では、 WDが一定とされている点である。  The difference between the sixth embodiment and the fifth embodiment is that, in the fifth embodiment, the relative distance in the optical axis direction between the objective lens 102 and the surface of the Ueno or A, that is, the force with which the WD is not constant. On the other hand, in the sixth embodiment, the WD is fixed.
即ち、ステージ及び対物レンズ 102の光軸方向における位置を、予め事前に設定 した後、両者の位置を常に同 Cf立置に維持するように設定を行うようになっている。従 つて、図 12に示すように、オートフォーカスのオフセット量を初期に設定した後に、再 度オフセット量を計算する必要がないので、オフセットにかける時間を短縮でき、スル 一プットの向上を図ることができる。  That is, after the positions of the stage and the objective lens 102 in the optical axis direction are set in advance, the settings are made so that both positions are always maintained at the same Cf standing position. Therefore, as shown in Fig. 12, there is no need to calculate the offset amount again after the initial setting of the autofocus offset amount, so that the time required for the offset can be reduced and the throughput can be improved. Can be.
[0068] 次に、本発明のレーザ加工装置の第 7実施形態を、図 13を参照して説明する。な お、この第 7実施形態においては、第 5実施形態における構成要素と同一の部分に ついては、同一の符号を付し、その説明を省略する。 第 7実施形態と第 5実施形態との異なる点は、第 5実施形態では、第 1のレンズ 104 が両凹レンズであつたのに対し、第 7実施形態のレーザ加工装置は、第 1のレンズ 10 4が凸レンズであり、平面側が第 2のレンズ 105側に向いて配されている点である。 本実施形態の場合も第 5実施形態と同様に、第 1のレンズ 104の位置に関係なぐ 平行光束状態で入射した光束は、常に同じ状態で屈折されて第 2のレンズ 105に入 射する。本実施形態のレーザ加工装置は、第 5実施形態のレーザ加工装置と同様の 作用効果を奏する。 Next, a laser processing apparatus according to a seventh embodiment of the present invention will be described with reference to FIG. In the seventh embodiment, the same components as those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted. The difference between the seventh embodiment and the fifth embodiment is that, in the fifth embodiment, the first lens 104 is a biconcave lens, whereas the laser processing apparatus of the seventh embodiment is different from the first lens 104 in the fifth embodiment. Reference numeral 104 denotes a convex lens, and the plane side is arranged to face the second lens 105 side. Also in the case of the present embodiment, similarly to the fifth embodiment, the light flux incident in the parallel light flux state regardless of the position of the first lens 104 is always refracted in the same state and enters the second lens 105. The laser processing apparatus of the present embodiment has the same functions and effects as the laser processing apparatus of the fifth embodiment.
[0069] 次に、本発明のレーザ加工装置の第 8実施形態を、図 14を参照して説明する。な お、この第 8実施形態においては、第 7実施形態における構成要素と同一の部分に ついては、同一の符号を付し、その説明を省略する。  Next, an eighth embodiment of the laser processing apparatus of the present invention will be described with reference to FIG. In the eighth embodiment, the same components as those in the seventh embodiment are denoted by the same reference numerals, and description thereof will be omitted.
第 8実施形態と第 7実施形態との異なる点は、第 7実施形態では、第 2レンズ群が、 1枚の凸レンズ、即ち、第 2のレンズ 105から構成されていたのに対し、第 8実施形態 の第 2レンズ群 120は、 2枚のレンズ 121、 122により構成されている点である。  The difference between the eighth embodiment and the seventh embodiment is that, in the seventh embodiment, the second lens group is composed of one convex lens, that is, the second lens 105. The second lens group 120 of the embodiment is configured by two lenses 121 and 122.
即ち、本実施形態の第 2レンズ群 120は、図 14に示すように、第 1レンズ群である凸 レンズ 104側に配された両凹レンズ 121及びこの両凹レンズ 121に隣接して配された 両凸レンズ 122により構成されている。なお、第 2レンズ群 120全体の後側焦点位置 力 対物レンズ 102の入射瞳位置の近傍に位置するようになっている。  That is, as shown in FIG. 14, the second lens group 120 according to the present embodiment includes a biconcave lens 121 disposed on the convex lens 104 side as the first lens group and a biconcave lens 121 disposed adjacent to the biconcave lens 121. It is composed of a convex lens 122. The rear focal position of the entire second lens group 120 is positioned near the entrance pupil position of the objective lens 102.
[0070] 本実施形態のレーザ加工装置は、第 7実施形態のレーザ加工装置と同様の作用 効果を奏することができ、更に、第 2レンズ群 120と対物レンズ 102との間隔 (距離)を 大きくすることができ、その間に他の観察系等を配置することが可能となり、設計の自 由度を向上することができる。 [0070] The laser processing apparatus of the present embodiment can provide the same functions and effects as the laser processing apparatus of the seventh embodiment, and further increases the distance (distance) between the second lens group 120 and the objective lens 102. In the meantime, other observation systems and the like can be arranged, and the degree of freedom in design can be improved.
[0071] 次に、本発明のレーザ加工装置の第 9実施形態を、図 15を参照して説明する。な お、この第 9実施形態においては、第 5実施形態における構成要素と同一の部分に ついては、同一の符号を付し、その説明を省略する。 Next, a ninth embodiment of the laser processing apparatus of the present invention will be described with reference to FIG. In the ninth embodiment, the same components as those in the fifth embodiment are denoted by the same reference numerals, and description thereof will be omitted.
第 9実施形態と第 5実施形態との異なる点は、第 5実施形態では、第 1レンズ群が、 1枚の両凹レンズ、即ち、第 1のレンズ 104から構成されていたのに対し、第 9実施形 態の第 1レンズ群 125は、 2枚のレンズ 126、 127により構成されている点である。 即ち、本実施形態の第 1レンズ群 125は、図 15に示すように、凸部をレーザ光源及 び平行光束手段側に向けて配された凸レンズ 126及びこの凸レンズ 126に隣接して 配された両凹レンズ 127により構成されている。また、本実施形態の第 2レンズ群は、 1枚の両凸レンズ 128から構成されている。 The difference between the ninth embodiment and the fifth embodiment is that, in the fifth embodiment, the first lens group is composed of one biconcave lens, that is, the first lens 104. The first lens group 125 of the ninth embodiment is configured by two lenses 126 and 127. That is, as shown in FIG. 15, the first lens group 125 of the present embodiment has a convex portion with a laser light source. And a biconcave lens 127 disposed adjacent to the convex lens 126. The second lens group according to the present embodiment includes one biconvex lens 128.
本実施形態の場合も第 5実施形態と同様に、第 1レンズ群 125の位置に関係なぐ 平行光束状態で入射した光束は、常に同じ状態で屈折されて第 2レンズ 128に入射 する。  Also in the case of the present embodiment, similarly to the fifth embodiment, the light flux incident in the parallel light flux state regardless of the position of the first lens group 125 is always refracted in the same state and enters the second lens 128.
本実施形態のレーザ光装置は、第 5実施形態のレーザ加工装置と同様の作用効果 を奏する。  The laser light device of the present embodiment has the same functions and effects as the laser processing device of the fifth embodiment.
[0072] なお、本発明の技術範囲は、上記第 5〜第 9実施形態に限定されるものではなぐ 本発明の趣旨を逸脱しない範囲において、種々の変更をカ卩えることが可能である。 例えば、第 1レンズ群及び第 2レンズ群は、上記第 5実施形態のように、 1枚のレン ズにより構成しても構わないし、第 7実施形態や第 8実施形態のように、 1枚以上のレ ンズにより構成しても構わない。また、各レンズはその種類、例えば、凸レンズ、凹レ ンズゃ両凸レンズに限定はされず、自由に糸且み合わせて設計して構わない。  The technical scope of the present invention is not limited to the fifth to ninth embodiments. Various changes can be made without departing from the spirit of the present invention. For example, the first lens group and the second lens group may be constituted by one lens as in the fifth embodiment, or may be constituted by one lens as in the seventh and eighth embodiments. The above lens may be used. Further, each lens is not limited to its type, for example, a convex lens, a concave lens, or a biconvex lens, and may be designed by freely joining together.
[0073] 特に、上記第 5〜第 9実施形態において、移動手段 106が、第 1レンズ群を、下記 式を満たすように移動させるように設定すると良 、。  In particular, in the fifth to ninth embodiments, it is preferable that the moving unit 106 is set so as to move the first lens group so as to satisfy the following expression.
1/ I f I < o. 01  1 / I f I <o. 01
なお、 I f Iは、第 1レンズ群と第 2レンズ群との合成焦点距離である。こうすることで Note that I f I is a composite focal length of the first lens group and the second lens group. By doing this
、ァフォーカルな部分を持たせることができる。 , It can have an afocal part.
[0074] また、上記第 5〜第 9実施形態において、下記式を満たすように第 2レンズ群を設定 すると良い。  In the fifth to ninth embodiments, the second lens group may be set so as to satisfy the following expression.
f2>0  f2> 0
なお、 f2は、第 2レンズ群の焦点距離である。  Here, f2 is the focal length of the second lens group.
集光光学系の入射瞳位置は、集光光学系内にあることも多いが、第 2レンズ群を正 パワー（凸レンズ）にすることで、集光光学系 103の入射瞳位置が光学系内に存在し たとしても、第 2レンズ群の後側焦点位置を集光光学系 103の入射瞳位置に一致さ せることができる。  The entrance pupil position of the condensing optical system is often located in the condensing optical system, but by setting the second lens group to a positive power (convex lens), the entrance pupil position of the condensing optical system 103 is set in the optical system. Even if it exists, the rear focal position of the second lens group can be matched with the entrance pupil position of the condenser optical system 103.
[0075] また、上記第 5〜第 9実施形態において、下記式を満たすように第 1レンズ群及び 第 2レンズ群を設定すると良い。 In the fifth to ninth embodiments, the first lens unit and It is better to set the second lens group.
fl < 0  fl <0
1≤ I Ϊ2/Ϊ1 I ≤5  1≤ I Ϊ2 / Ϊ1 I ≤5
なお、 flは、第 1レンズ群の焦点距離であり、 f2は、第 2レンズ群の焦点距離である 第 1レンズ群を負パワー（凹レンズ)、第 2レンズ群を正パワー（凸レンズ）にすること で、構成のコンパクトィ匕を図ることができる。また、 l≤f2/flであるので、第 1レンズ 群を簡単に構成できる。そのため、安価にできるば力りでなぐ性能劣化を抑えること ができる。また、 I f2/fl I ≤ 5であるので、光学系をコンパクトに構成できる。  Note that fl is the focal length of the first lens group, and f2 is the focal length of the second lens group. The first lens group has negative power (concave lens) and the second lens group has positive power (convex lens). Thus, the configuration can be made compact. Also, since l≤f2 / fl, the first lens group can be easily configured. For this reason, it is possible to suppress the performance degradation that can be achieved by the power if possible at low cost. Since I f2 / fl I ≤ 5, the optical system can be made compact.
[0076] また、第 1レンズ群及び第 2レンズ群の設定は、上述したように、 fl < 0、 1≤ I f2/ fl I≤ 5だけに限らず、例えば、上記第 5〜第 9実施形態において、下記式を満たす ように設定しても良い。 Further, as described above, the settings of the first lens group and the second lens group are not limited to fl <0 and 1 ≦ I f2 / fl I ≦ 5. In the embodiment, the setting may be made so as to satisfy the following expression.
fl >0  fl> 0
0. 5≤ I Ϊ1/Ϊ2 I ≤2  0.5 ≤ I Ϊ1 / Ϊ2 I ≤2
こうすることで、両レンズ群の焦点距離を正の焦点距離にでき、単純な構成で、等 倍率近くでリレーさせることができる。  By doing so, the focal lengths of both lens groups can be set to a positive focal length, and relaying can be performed with a simple configuration near the same magnification.
[0077] また、上記第 5〜第 9実施形態では、制御部により移動手段を自動的に制御するよ うに構成したが、制御部による計算結果に基づいて、移動手段を作動させて第 1のレ ンズ群の位置を移動させても構わな 、。 Further, in the fifth to ninth embodiments, the moving means is automatically controlled by the control unit. However, based on the calculation result by the control unit, the moving means is operated to perform the first operation. You can move the lens group.
また、本発明の光学系を、図 16に示すような収差補正光学系に利用して球面収差 補正を行っても構わない。即ち、収差補正光学系 140は、図示しない光源からの光 束を集光させる光学系であり、下記式を満たす複数のレンズ 141、 142、 143を排他 で光路中に揷脱可能に配して 、る。  Further, the optical system of the present invention may be used for an aberration correction optical system as shown in FIG. 16 to perform spherical aberration correction. That is, the aberration correction optical system 140 is an optical system that condenses a light beam from a light source (not shown), and a plurality of lenses 141, 142, and 143 that satisfy the following expression are exclusively disposed in the optical path so as to be able to be removed. RU
2 (d2+l X f-l X d) NA=f X a 2 (d 2 + l X fl X d) NA = f X a
なお、上記 dは、対物レンズ 102を含む集光光学系 103の入射瞳位置カゝら複数の レンズ 141、 142、 143までの距離であり、上記 1は、集光光学系 103の入射瞳位置 から光源位置までの距離であり、上記 fは、複数のレンズ 141、 142、 143の焦点位 置であり、上記 NAは、光源の NA (集光レンズから見た NA)であり、上記 aは、集光 光学系 103の入射瞳径である。また、光束は、発散光状態であり、上記複数のレンズ 141、 142、 143は、凸レンズとして ヽる。 Note that d is the distance from the entrance pupil position of the condenser optical system 103 including the objective lens 102 to the plurality of lenses 141, 142, and 143, and 1 is the entrance pupil position of the condenser optical system 103. Where f is the focal position of the plurality of lenses 141, 142, and 143, NA is the NA of the light source (NA as viewed from the condenser lens), and a is the a , Condensing This is the entrance pupil diameter of the optical system 103. The light beam is in a divergent light state, and the plurality of lenses 141, 142, and 143 function as convex lenses.
このように構成した収差補正光学系 140においては、発散光源の場合に、ウェハ A 中の深さが異なる部位を観察 (集光)しょうとした場合でも、光量一定、瞳面内での光 量分布一定で球面収差の発生量を抑えた観察 (集光)を行うことができる。また、従 来のように、補正環対物レンズ等の高価な対物レンズを組み合わせたり、厚みの異な るガラス等を交換する必要がな 、。  In the aberration correction optical system 140 configured as described above, even if a divergent light source is used to observe (collect) a portion of the wafer A with a different depth, the light amount is constant, and the light amount in the pupil plane is increased. Observation (condensing) with a constant distribution and a reduced amount of spherical aberration can be performed. In addition, it is not necessary to combine expensive objective lenses such as a correction ring objective lens, or to exchange glass or the like having different thicknesses as before.
[0078] また、上述した図 16に示す収差補正光学系 140では、発散光束中に凸レンズであ る複数のレンズ 141、 142、 143を配したが、図 17に示すように、収束光束中に複数 のレンズ 141、 142、 143を配しても構わない。この場合には、複数のレンズ 141、 14 2、 143は凹レンズにすれば良い。 In the aberration correction optical system 140 shown in FIG. 16 described above, a plurality of lenses 141, 142, and 143, which are convex lenses, are arranged in the divergent light beam. However, as shown in FIG. A plurality of lenses 141, 142, 143 may be arranged. In this case, the plurality of lenses 141, 142, and 143 may be concave lenses.
更に、図 18に示すように、凹レンズである複数のレンズ 141、 142、 143を、平行光 束中に配しても構わない。  Further, as shown in FIG. 18, a plurality of lenses 141, 142, and 143, which are concave lenses, may be arranged in a parallel light beam.
更には、図 19に示すように、平行光束をー且凸レンズ 145で収束光に変換した後 、複数のレンズ 141、 142、 143を配しても構わない。  Further, as shown in FIG. 19, a plurality of lenses 141, 142, 143 may be arranged after the parallel light beam is converted into convergent light by the negative lens 145.
[0079] また、上記第 5〜第 9実施形態において、ウェハ内にレーザ光を集光させたが、ゥ ェハに限らず媒質中に集光させれば構わない。また、集光させたい距離として、ゥェ ハの表面から 50 m、 75 m、 100 μ mの距離とした力 これらの距離に限らず、任 意に設定して構わない。また、ステージを移動させて、対物レンズとウェハの表面との 光軸方向の相対的な距離を変化させたが、これに限らず、例えば、対物レンズを、ピ ェゾ素子等を利用して移動させることで、相対的な距離を変化させても構わない。 また、上記第 5実施形態で説明した観察光学系は一例であり、対物レンズの下面か らウェハの表面までの距離を所定距離に維持可能であれば、レンズ等の各光学系を 組み合わせて構成して構わな!/、。 In the fifth to ninth embodiments, the laser beam is focused on the wafer. However, the laser beam is not limited to the wafer and may be focused on the medium. In addition, the distance to be condensed is set to a distance of 50 m, 75 m, or 100 μm from the surface of the wafer. The force is not limited to these distances, and may be set arbitrarily. In addition, the relative distance in the optical axis direction between the objective lens and the surface of the wafer was changed by moving the stage. However, the present invention is not limited to this. For example, the objective lens may be changed by using a piezo element or the like. The relative distance may be changed by moving. The observation optical system described in the fifth embodiment is an example, and is configured by combining optical systems such as lenses as long as the distance from the lower surface of the objective lens to the surface of the wafer can be maintained at a predetermined distance. You can do it! /
[0080] また、本発明には、以下のものが含まれる。 [0080] Further, the present invention includes the following.
〔付記項 1〕  (Appendix 1)
レーザ光を射出するレーザ光源と；  A laser light source for emitting laser light;
このレーザ光源から射出された前記レーザ光の光束を平行光束にする平行光束手 段と； A parallel light beam for converting the light beam of the laser light emitted from the laser light source into a parallel light beam; Steps;
前記平行光束状態の前記レーザ光を媒質中に集光させる集光光学系と； 前記平行光束手段と前記集光光学系との間の前記平行光束中に、この平行光束 の光軸方向に沿って移動可能に配されて、 1枚以上のレンズにより構成された第 1レ ンズ群と；  A condensing optical system for condensing the laser light in the parallel light beam state into a medium; and a light beam, which extends along the optical axis direction of the parallel light beam in the parallel light beam between the parallel light beam means and the light condensing optical system. A first lens group, which is movably disposed and comprises one or more lenses;
この第 1レンズ群と前記集光光学系との間の前記平行光束中に固定された状態で 配されて、 1枚以上のレンズにより構成された第 2レンズ群と；  A second lens group, which is fixedly disposed in the parallel light flux between the first lens group and the condensing optical system, and includes one or more lenses;
前記レーザ光を集光させたい前記媒質の屈折率及び媒質の表面から集光させた い位置までの距離に応じて、前記第 1のレンズ群を移動させる移動手段と； を備え、  Moving means for moving the first lens group in accordance with the refractive index of the medium on which the laser light is to be focused and the distance from the surface of the medium to the position on which the laser light is to be focused;
前記第 2レンズ群は、後側焦点位置が前記集光光学系の入射瞳位置の少なくとも 近傍に配されて 、るレーザ加工装置。  A laser processing apparatus, wherein the second lens group has a rear focal point located at least near an entrance pupil position of the light-collecting optical system.
〔付記項 2〕  (Appendix 2)
付記項 1に記載のレーザ加工装置であって、  The laser processing apparatus according to claim 1, wherein
前記集光光学系に連係して設けられ、集光光学系の下面から前記媒質の表面ま での距離を所定の距離に維持する観察光学系を備え、  An observation optical system provided in association with the condensing optical system and maintaining a predetermined distance from the lower surface of the condensing optical system to the surface of the medium;
この観察光学系が、フォーカス検出手段又はオートフォーカス機構を備える。 〔付記項 3〕  This observation optical system includes a focus detection unit or an autofocus mechanism. (Appendix 3)
付記項 1又は 2に記載のレーザ加工装置であって、  The laser processing apparatus according to claim 1 or 2,
前記集光光学系と前記媒質の表面との光軸方向の相対的な距離が一定である。 〔付記項 4〕  The relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium is constant. (Appendix 4)
付記項 1から 3のいずれ力 1項に記載のレーザカ卩ェ装置であって、  The laser camera device according to any one of the additional items 1 to 3, wherein
前記第 1レンズ群と前記第 2レンズ群との合焦距離を I f Iとする場合、前記移動手 段が、前記第 1レンズ群を、下記式を満たす位置に移動させる。  When the focusing distance between the first lens group and the second lens group is I f I, the moving means moves the first lens group to a position satisfying the following expression.
1/ I f I < o. 01  1 / I f I <o. 01
〔付記項 5〕  (Appendix 5)
付記項 1から 4のいずれ力 1項に記載のレーザ加工装置であって、  The laser processing apparatus according to any one of additional items 1 to 4, wherein:
第 2レンズ群の焦点距離を f2とする場合、前記第 2レンズ群が、下記式を満たす。 f2>0 When the focal length of the second lens group is f2, the second lens group satisfies the following equation. f2> 0
〔付記項 6〕  (Appendix 6)
付記項 1から 5のいずれ力 1項に記載のレーザカ卩ェ装置であって、  The laser camera device according to any one of additional items 1 to 5, wherein
前記第 1レンズ群の焦点距離を flとし、第 2レンズ群の焦点距離を f2とする場合、 前記第 1レンズ群及び前記第 2レンズ群が下記式を満たす。  When the focal length of the first lens group is fl and the focal length of the second lens group is f2, the first lens group and the second lens group satisfy the following equation.
fl<0  fl <0
1≤ I Ϊ1/Ϊ2 I≤5  1≤ I Ϊ1 / Ϊ2 I≤5
〔付記項 7〕  (Appendix 7)
付記項 1から 5のいずれ力 1項に記載のレーザカ卩ェ装置であって、  The laser camera device according to any one of additional items 1 to 5, wherein
前記第 1レンズ群の焦点距離を flとし、第 2レンズ群の焦点距離を f2とする場合、 前記第 1レンズ群及び前記第 2レンズ群が、下記式を満たす。  When the focal length of the first lens group is fl and the focal length of the second lens group is f2, the first lens group and the second lens group satisfy the following equation.
fl>0  fl> 0
0. 5≤ I Ϊ1/Ϊ2 I≤2  0.5 ≤ I Ϊ1 / Ϊ2 I≤2
〔付記項 8〕  (Appendix 8)
レーザ光を射出するレーザ光源と；  A laser light source for emitting laser light;
前記レーザ光を媒質中に集光させる集光光学系と;を含み、  A focusing optical system for focusing the laser light into a medium;
前記レーザ光を集光させた 、媒質の屈折率、媒質の表面から集光させた!/、位置ま での距離に応じて、前記集光光学系の収束又は発散光束中に下記式を満足する複 数のレンズを排他で挿脱可能に配置したレーザ集光光学系を有するレーザ加工装 置。  The laser light was focused, the refractive index of the medium, and focused from the surface of the medium! /, Depending on the distance to the position, the following formula was satisfied in the convergent or divergent light flux of the focusing optical system. Laser processing equipment with a laser focusing optical system in which multiple lenses that can be inserted and removed are exclusively inserted.
2(d2+lXf-lXd)NA=fXa 2 (d 2 + lXf-lXd) NA = fXa
d;集光光学系の入射瞳位置から複数のレンズまでの距離  d; distance from entrance pupil position of condensing optical system to multiple lenses
1；集光光学系の入射瞳位置から光源位置までの距離  1; Distance from the entrance pupil position of the condensing optical system to the light source position
f；複数のレンズの焦点位置  f; focal positions of multiple lenses
NA；光源の開口数 (集光レンズから見た開口数）  NA; numerical aperture of light source (numerical aperture viewed from condensing lens)
a;集光光学系の入射瞳径  a; entrance pupil diameter of condensing optical system
〔付記項 9〕  (Appendix 9)
光軸に平行なレーザ光束を射出するレーザ光源と； 前記レーザ光束を媒質中に集光させる光学系と；を含み、 A laser light source for emitting a laser beam parallel to the optical axis; An optical system for condensing the laser beam into a medium;
前記レーザ光束を集光させた!/、媒質の屈折率、媒質の表面から集光させた!/、位置 までの距離に応じて、レーザ光束中に下記式を満足する複数のレンズを排他で挿脱 可能に配置したレーザ集光光学系を有するレーザ加工装置。  The laser beam was condensed! /, The refractive index of the medium, the beam was condensed from the surface of the medium! /, Depending on the distance to the position, a plurality of lenses satisfying the following equation were exclusively excluded in the laser beam. A laser processing device that has a laser focusing optical system that can be inserted and removed.
b (f -d) /f = a  b (f -d) / f = a
b ;光源からの平行光束径  b; diameter of parallel light beam from light source
d ;集光光学系の入射瞳位置から複数のレンズまでの距離  d: Distance from entrance pupil position of condensing optical system to multiple lenses
f；複数のレンズの焦点位置  f; focal positions of multiple lenses
a ;集光光学系の入射瞳径  a; entrance pupil diameter of condensing optical system
産業上の利用可能性  Industrial applicability
[0081] 本発明に係るレーザ集光光学系によれば、集光させた!/、媒質の屈折率及び媒質 の表面から集光させたい位置までの距離に応じて、レーザ発散点移動手段によりレ 一ザ発散点をレーザ光の光軸上に沿って移動させるので、媒質中の深さが異なるそ れぞれの位置で、球面収差の発生量を極力抑えることができる。従って、レーザ光を 所望する媒質の深さに効率良く集光させることができ、集光性能の向上を図ることが できる。 According to the laser condensing optical system according to the present invention, the laser diverging point moving means is used in accordance with the condensed light !, the refractive index of the medium, and the distance from the surface of the medium to the position where the light is condensed. Since the laser divergence point is moved along the optical axis of the laser light, it is possible to minimize the amount of spherical aberration generated at different positions in the medium at different depths. Therefore, the laser light can be efficiently condensed to a desired depth of the medium, and the light condensing performance can be improved.
特に、レーザ発散点を移動させるだけであるので、従来のように手間をかけることな ぐ容易に球面収差補正を行うことができると共に特別な光学系を備える必要がない ので、構成のシンプルィ匕を図ることができ、低コストィ匕を図ることができる。  In particular, since only the laser divergence point is moved, spherical aberration correction can be easily performed without any trouble as in the related art, and there is no need to provide a special optical system. Therefore, low cost dangling can be achieved.
また、上記レーザ集光光学系を備えたレーザ加工装置によれば、媒質中の異なる 各深さに、球面収差の発生を極力抑えた状態でレーザ光の集光を効率良く行えるの で、正確なレーザ力卩ェを行うことができる。  Further, according to the laser processing apparatus provided with the above laser focusing optical system, the laser beam can be efficiently focused at different depths in the medium while suppressing the occurrence of spherical aberration as much as possible. Laser beam can be performed.
[0082] 本発明に係るレーザ加工装置の第 1〜第 3の態様によれば、集光させたい媒質の 屈折率及び媒質表面から集光させたい位置までの距離に応じて、第 1レンズ群を移 動させることで、第 2レンズ群に入射するレーザ光の位置を変更できる、即ち、集光光 学系から見た光源位置の変更が行えるので、所望する位置 (深さ）に球面収差の発 生量を極力抑えた状態でレーザ光を集光させることができる。従って、レーザ加工を 高精度に行うことができる。 また、後側焦点位置が集光光学系の入射瞳位置に一致した第 2レンズ群により、集 光光学系の入射瞳に入射する光束径を変化させることがないので、入射光量や、瞳 面内での光量分布を一定にすることができ、集光性能の変化を抑えることができる。 更に、第 1レンズ群を移動させるだけで、光源位置の変更が行えるので、構成のシ ンプルイ匕を図ることができ、手間をかけることなく容易に球面収差補正を行うことがで きる。 [0082] According to the first to third aspects of the laser processing apparatus according to the present invention, the first lens group depends on the refractive index of the medium to be focused and the distance from the surface of the medium to the position to be focused. By moving the laser beam, the position of the laser beam incident on the second lens group can be changed, that is, the light source position can be changed from the viewpoint of the condensing optical system. The laser beam can be focused while minimizing the amount of light generation. Therefore, laser processing can be performed with high accuracy. In addition, the second lens group whose rear focal point coincides with the entrance pupil position of the condenser optical system does not change the diameter of the light beam incident on the entrance pupil of the condenser optical system. It is possible to make the light amount distribution in the inside constant, and it is possible to suppress a change in the light collecting performance. Further, since the position of the light source can be changed only by moving the first lens group, the configuration can be simplified, and spherical aberration can be easily corrected without any trouble.

Claims

請求の範囲 The scope of the claims
[1] レーザ光を出射するレーザ光源と；  [1] a laser light source for emitting laser light;
このレーザ光源と媒質との間に配されて前記レーザ光を媒質中に集光させる集光 光学系と；  A condensing optical system disposed between the laser light source and the medium for condensing the laser light into the medium;
前記レーザ光のレーザ発散点の位置を、レーザ光を集光させた 、前記媒質の屈折 率及び前記媒質の表面から集光させた!/、位置までの距離に応じて、前記レーザ光 の光軸上に沿って移動可能なレーザ発散点移動手段と；  The position of the laser divergence point of the laser light was focused on the laser light, the refractive index of the medium was focused on the surface of the medium, and the light of the laser light was changed according to the distance to the position. Laser divergence point moving means movable along an axis;
を備えて ヽるレーザ集光光学系。  A laser focusing optics equipped with:
[2] 請求項 1に記載のレーザ集光光学系であって、  [2] The laser focusing optical system according to claim 1,
前記レーザ発散点移動手段が、予め測定された前記集光光学系の波面データに 基づ 、てレーザ発散点の位置を設定する。  The laser divergence point moving means sets the position of the laser divergence point based on the wavefront data of the condensing optical system measured in advance.
[3] 請求項 1に記載のレーザ集光光学系であって、 [3] The laser focusing optical system according to claim 1,
前記集光光学系に連携して設けられ、集光光学系の下面から前記媒質の表面ま での距離を所定の距離に維持する観察光学系を備え、  An observation optical system provided in cooperation with the condensing optical system to maintain a predetermined distance from a lower surface of the condensing optical system to a surface of the medium;
この観察光学系が、フォーカス検出手段又はオートフォーカス機構を備える。  This observation optical system includes a focus detection unit or an autofocus mechanism.
[4] 請求項 1に記載のレーザ集光光学系であって、 [4] The laser focusing optical system according to claim 1,
前記集光光学系と前記媒質の表面との光軸方向の相対的な距離が一定である。  The relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium is constant.
[5] 請求項 1に記載のレーザ集光光学系を備えたレーザ加工装置。 [5] A laser processing apparatus comprising the laser focusing optical system according to claim 1.
[6] レーザ光を射出するレーザ光源と； [6] a laser light source for emitting laser light;
このレーザ光源から射出された前記レーザ光の光束を平行光束にする平行光束手 段と；  A parallel light beam means for converting the light beam of the laser light emitted from the laser light source into a parallel light beam;
前記平行光束状態の前記レーザ光を媒質中に集光させる集光光学系と； 前記平行光束手段と前記集光光学系との間の前記平行光束中に、この平行光束 の光軸方向に沿って移動可能に配されて、 1枚以上のレンズにより構成された第 1レ ンズ群と；  A condensing optical system for condensing the laser light in the parallel light beam state into a medium; and a light beam, which extends along the optical axis direction of the parallel light beam in the parallel light beam between the parallel light beam means and the light condensing optical system. A first lens group, which is movably disposed and comprises one or more lenses;
この第 1レンズ群と前記集光光学系との間の前記平行光束中に固定された状態で 配されて、 1枚以上のレンズにより構成された第 2レンズ群と；  A second lens group, which is fixedly disposed in the parallel light flux between the first lens group and the condensing optical system, and includes one or more lenses;
前記レーザ光を集光させた!/、前記媒質の屈折率及び媒質表面から集光させた!/、 位置までの距離に応じて、前記第 1のレンズ群を移動させる移動手段と； を備え、 The laser light was focused! /, The refractive index of the medium and focused from the medium surface! / Moving means for moving the first lens group according to a distance to a position;
前記第 2レンズ群が、後側焦点位置が前記集光光学系の入射瞳位置の少なくとも 近傍に配されている  The second lens group has a rear focal point located at least near the entrance pupil position of the light-collecting optical system.
レーザ加工装置。  Laser processing equipment.
[7] 請求項 6記載のレーザ加工装置であって、 [7] The laser processing apparatus according to claim 6, wherein
前記集光光学系に連係して設けられ、集光光学系の下面から前記媒質の表面ま での距離を所定の距離に維持する観察光学系を備え、  An observation optical system provided in association with the condensing optical system and maintaining a predetermined distance from the lower surface of the condensing optical system to the surface of the medium;
この観察光学系が、フォーカス検出手段又はオートフォーカス機構を備える。  This observation optical system includes a focus detection unit or an autofocus mechanism.
[8] 請求項 7に記載のレーザカ卩ェ装置であって、 [8] The laser camera apparatus according to claim 7, wherein
前記集光光学系と前記媒質の表面との光軸方向の相対的な距離が一定である。  The relative distance in the optical axis direction between the light-collecting optical system and the surface of the medium is constant.
[9] 請求項 6に記載のレーザ加工装置であって、 [9] The laser processing apparatus according to claim 6, wherein
前記第 1レンズ群と前記第 2レンズ群との合焦距離を I f Iとした場合、前記移動手 段が、前記第 1レンズ群を、下記式を満たす位置に移動させる。  If the focusing distance between the first lens group and the second lens group is I f I, the moving means moves the first lens group to a position that satisfies the following equation.
1/ I f I < o. 01  1 / I f I <o. 01
[10] 請求項 6に記載のレーザ加工装置であって、  [10] The laser processing apparatus according to claim 6, wherein
前記第 2レンズ群の焦点距離を f2とした場合、前記第 2レンズ群が、下記式を満た す。  When the focal length of the second lens group is f2, the second lens group satisfies the following equation.
f2 >0  f2> 0
[11] 請求項 6に記載のレーザ加工装置であって、  [11] The laser processing apparatus according to claim 6, wherein
前記第 1レンズ群の焦点距離を fl、前記第 2レンズ群の焦点距離を f2とした場合、 前記第 1レンズ群及び前記第 2レンズ群が、下記式を満たす。  When the focal length of the first lens group is fl and the focal length of the second lens group is f2, the first lens group and the second lens group satisfy the following equation.
fl < 0  fl <0
かつ、 1≤ I Ϊ1/Ϊ2 I ≤5  And 1≤ I Ϊ1 / Ϊ2 I ≤5
[12] 請求項 6に記載のレーザ加工装置であって、 [12] The laser processing apparatus according to claim 6, wherein
前記第 1レンズ群の焦点距離を fl、前記第 2レンズ群の焦点距離を f2とした場合、 前記第 1レンズ群及び前記第 2レンズ群が、下記式を満たす。  When the focal length of the first lens group is fl and the focal length of the second lens group is f2, the first lens group and the second lens group satisfy the following equation.
fl >0 かつ、 0.5≤ I fl/f2 I≤2 fl> 0 And 0.5≤ I fl / f2 I≤2
[13] レーザ光を射出するレーザ光源と； [13] a laser light source for emitting laser light;
前記レーザ光を媒質中に集光させる集光光学系と;を含み、  A focusing optical system for focusing the laser light into a medium;
前記レーザ光を集光させた 、媒質の屈折率、媒質の表面から集光させた!/、位置ま での距離に応じて、前記集光光学系の収束又は発散光束中に下記式を満足する複 数のレンズを排他で挿脱可能に配置したレーザ集光光学系を有するレーザ加工装 置。  The laser light was focused, the refractive index of the medium, and focused from the surface of the medium! /, Depending on the distance to the position, the following formula was satisfied in the convergent or divergent light flux of the focusing optical system. Laser processing equipment with a laser focusing optical system in which multiple lenses that can be inserted and removed are exclusively inserted.
2(d2+lXf-lXd)NA=fXa 2 (d 2 + lXf-lXd) NA = fXa
ただし、 d；集光光学系の入射瞳位置力 複数のレンズまでの距離  However, d: the position of the entrance pupil of the condensing optical system Distance to multiple lenses
1;集光光学系の入射瞳位置から光源位置までの距離  1; distance from the entrance pupil position of the condensing optical system to the light source position
f；複数のレンズの焦点位置  f; focal positions of multiple lenses
NA；光源の開口数 (集光レンズから見た開口数）  NA; numerical aperture of light source (numerical aperture viewed from condensing lens)
a;集光光学系の入射瞳径  a; entrance pupil diameter of condensing optical system
[14] 光軸に平行なレーザ光束を射出するレーザ光源と； [14] a laser light source for emitting a laser beam parallel to the optical axis;
前記レーザ光束を媒質中に集光させる光学系と；を含み、  An optical system for condensing the laser beam into a medium;
前記レーザ光束を集光させた!/、媒質の屈折率、媒質の表面から集光させた!/、位置 までの距離に応じて、レーザ光束中に下記式を満足する複数のレンズを排他で挿脱 可能に配置したレーザ集光光学系を有するレーザ加工装置。  The laser beam was condensed! /, The refractive index of the medium, the beam was condensed from the surface of the medium! /, Depending on the distance to the position, a plurality of lenses satisfying the following equation were exclusively excluded in the laser beam. A laser processing device that has a laser focusing optical system that can be inserted and removed.
b(f-d)/f = a  b (f-d) / f = a
ただし、 b;光源力 の平行光束径  Where, b: diameter of the parallel light flux of the light source power
d;集光光学系の入射瞳位置カゝら複数のレンズまでの距離 f；複数のレンズの焦点位置  d; distance of the entrance pupil position of the condensing optical system to multiple lenses f; focal positions of multiple lenses
a;集光光学系の入射瞳径  a; entrance pupil diameter of condensing optical system
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US9457424B2 (en) 2008-11-28 2016-10-04 Hamamatsu Photonics K.K. Laser machining device
US8755107B2 (en) 2010-01-27 2014-06-17 Hamamatsu Photonics K.K. Laser processing system
JPWO2016132554A1 (en) * 2015-02-20 2017-04-27 技術研究組合次世代３Ｄ積層造形技術総合開発機構 Optical processing head, optical processing apparatus, control method thereof, and control program
US10532427B2 (en) 2015-02-20 2020-01-14 Technology Research Association For Future Additive Manufacturing Optical processing head, optical machining apparatus, and control method and control program of optical processing head

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US7333255B2 (en) 2008-02-19
US20060228095A1 (en) 2006-10-12
US20080029497A1 (en) 2008-02-07
EP1684109B1 (en) 2013-06-26
EP1684109A1 (en) 2006-07-26
KR20070005928A (en) 2007-01-10
TW200538223A (en) 2005-12-01
US8022332B2 (en) 2011-09-20
EP1684109A4 (en) 2007-06-13
TWI348408B (en) 2011-09-11
KR100789538B1 (en) 2007-12-28

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